In this “easy” glossary you can find words or terms with their easiest possible definition or explanation in English. The purpose is to help a learner of English understand this site as well as possible, not to provide completely accurate scientific definitions.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A
ACE2
an enzyme molecule on the cell membrane of some cells
active compound
the molecule in a drug that works to treat you
acute respiratory distress syndrome (ARDS)
a condition in the lungs with more and more fluid in the alveoli, which
keeps oxygen from going into the blood
adenine
one of the four nucleotide bases in DNA or RNA
adenovirus
one kind of common cold virus
aerosol
tiny drops that stay floating in the air
alveolus, alveoli (plural)
a tiny hollow sac at the end of the bronchial tubes of the lungs
amino acid
a molecule that is one piece of a protein
animal
a living thing that moves, like a mammal, a bird or a frog
androgen
a male sex hormone (for example testosterone)
anti-clotting medication
medicine that keeps blood from clotting,
Anti-clotting medication reduces the coagulant properties of the blood.
antibody
a protein that attaches to an virus to prevent it from attaching to cells
antibody test
a test to find out if a specific antibody is in the blood
anticoagulant (adjective & noun)
(adjective) slowing or reducing the coagulation (clotting) of the blood
(noun) a substance that slows or reduces the coagulation (clotting) of the blood
anti-inflammatory drug
a drug that reduces inflammation
antigen
foreign material that triggers a production of antibodies against it
antiviral drug
a drug that is works against viruses
arrhythmia
an irregular or abnormal heartbeat
aspirate (verb)
to breath in or to breath something in
aspiration
breathing in or breathing something in
asymptomatic (adjective)
describes an person never being sick from a particular infection
atom
the smallest part of some things, like iron, that is still the same kind of thing
atomic particle
the tiny things inside an atom
autoimmune (adjective)
describes a disease that has the immune system attack a part of the body
B
bat
a mammal that can fly
A horseshoe bat is a kind of bat.
bind (verb)
to attach with a chemical bond
biodiversity
many different kinds of life in one place
biology
the science of life
blood
the red liquid that flows throughout people’s bodies
blood cell
a cell of the blood
(Some blood cells are red. Others are white.)
blood clot
blood that becomes thick or solid, stopping the flow of blood
blood thinner
a drug that thins the blood (making it less easy to have clots)
blood vessel
big, smaller and tiny tubes that take blood everywhere in the body
body (or: human body)
all the matter of a person, including head, arms, legs, etc.
brain
the organ in the head that thinks and controls the body
breathing tube
a tube into the lungs for air to go in and out with a ventilator
bronchial tube
one of the tubes in the lungs (like a branch of a tree)
C
C-reactive protein (CRP)
a protein produced by the liver when there is inflammation somewhere in the body
capillary
a very small blood vessel (in which blood flows in the body)
capsid
a protein covering that is part of a coronavirus and contains RNA or DNA
SARS-CoV-2 has a coiled cylindrical capsid within a spherical
envelope, and its RNA is coiled within it.
carbon
one kind of atom found in life
Carbon is the black part of something that burned.
carbon dioxide
a small molecule (CO2), which is part of the air people breathe out
cardiac arrest
when the heart stops
cardiovascular (adjective)
of the heart and blood vessels
case
someone who is known to be infected
case mortality rate
the percentage of all known cases of a disease whereby the person died
cell
a very small living thing or a tiny part of anything that is alive
All living things are cells or have cells (except for viruses).
cell junction
the proteins between cells that keep them together
cell membrane
what is between the inside and outside of a cell (like a wall)
central nervous system (CNS)
the brain and the spinal chord
chain
a strand of a molecule such as RNA or DNA
chemokine
a kind of cytokine that attracts white blood cells to infected cells
and has other functions
chloroquine
a drug that was made to treat malaria
cleave (verb)
to split a molecule by breaking a chemical bond
clinical trial
an experiment that tests the effectiveness of a treatment or a vaccine in patients
clot
blood that is too thick or hard and cannot flow
clotting factors (or: coagulation factors)
the proteins in the blood that are required for
blood coagulation (blood clot formation)
cluster
a group of individuals with a known common original source of infection
coagulant (adjective)
blood-thickening
coagulate
(of the blood) to thicken
coagulation
the process of blood thickening
cocktail
a mixture of substances such as drugs
community spreading
spreading of an infection in population with unknown links
contact tracing
a search for the links between infected people
contagious
very infectious between people
containment
keeping a spreading infection under control within a population
control (verb)
(of a disease) to limit the spread or effect of a disease in a population
control group, control
a group in an experiment or trial that does not receive
a particular treatment so that a comparison can test a hypothesis
convalescent plasma
blood plasma from individuals who have recovered from a disease that is
transfused into patients so that antibodies in it may help in the recovery
coronavirus
a kind of virus shaped like a ball with spikes
SARS-CoV-19 is a kind of coronavirus.
cough
air very quickly leaving the mouth creating a sound in the throat
Covid toes
a strange rash of the toes caused by Covid-19
CPAP respirator
a device providing “continuous positive airway pressure” (CPAP) that
assists patients in breathing by keeping the alveoli from collapsing
cytokine
any of various molecules that signal (call for) an immune response
cytokine storm
a condition with high levels of cytokines causing an overactive immune response
D
D-dimer
a small protein fragment found in the blood after a blood clot degrades
data
information that can be represented with numbers
delayed chain termination
a way to stop the copying of an RNA strand several nucleotide bases
after some molecule attaches to the new strand
dexamethasone
a medicine that reduces inflammation
Dexamethasone is the first drug that was found to significantly
reduce the number of Covid-19 patients that die.
device
a thing that does something useful
diabetes
a disease with too much sugar in the blood
diarrhea
stools that flow too quickly
dimer
a molecule such as a protein with two parts that are the same
disease
a sickness
A disease makes people sick.
disinformation
misinformation that is spread by people who know it is wrong information
distend (verb)
to make something bigger
DNA
the long molecule containing all the information needed to make a living thing
double-blind (adjective)
(for a drug trial) where patients and doctors do not know
what drug the patient takes
(for example, the drug they are testing or a placebo)
droplet
a small drop of water or other liquid
A cloud in the sky has very many tiny droplets.
Droplets are smaller than raindrops.
Infected people can breathe out droplets that contain viruses!
Droplets are sometimes invisible.
A virus can stay inside droplets in the air.
drug
drug trial
an experiment that tests how good a drug works in patients
Conclusive results generally require one or more double-blind trials.
dysfunction
when a part of the body does not work correctly
E
electricity
a form of energy that moves through wires
electron
a thing inside an atom, an atomic particle
element
something that only contains one kind of atom
(Iron is an element.)
encephalitis
inflammation of the brain
endemic (adjective)
(of a disease) that comes back regularly (like every year) in a population
endothelial cell
a cell on the inside wall of blood vessels
or on an organ
energy
movement of matter and the movement of heat, light, electricity, etc.
ensemble projection
a merge (combination) of different models, such as for predicting deaths from Covid-19
enzyme
a protein that does some work, for example to put proteins together
envelope
the surface of a virus
epidemiologist
a professional trained to control the spread of a disease
epidemiology
the study of the spread and control of a disease in populations
evidence
available information that gives some indication of something being true
experiment
the scientific means to test a hypothesis
express (verb)
to cause genetic information (in DNA or RNA) to create molecules
expression
creating molecules from information in DNA or RNA
F
false negative
a test returning a negative result that should instead be a positive result
false positive
a test returning a positive result that should instead be a negative result
fever
a high temperature inside a person’s body
ferritin
a protein in mammals that serves to store iron in tissues
flatten the curve (verb)
(in an epidemic) to slow down the spread of a disease (in order to reduce
the expected hospital capacity required to treat it)
flush (verb)
to make water flow through the toilet
furin
an enzyme on the wall of some animal cells that
(possibly together with the TMPRSS2 enzyme) can cleave the SARS-CoV-2 spike,
which triggers a process to fuse the viral particle onto the cell membrane,
allowing the RNA to enter the host cell
G
gene
a nucleotide sequence in DNA or RNA that describes
the pieces that create a protein
genetic
relating to genes (in DNA or RNA)
genetic fingerprint
patterns in RNA or DNA that can identify the source
genetic material
genome
the total genetic information that defines a living thing
genomics
an application of the information in a genome
glycoprotein (or: glycopeptide)
a protein with carbohydrate groups on a polypeptide chain
goblet secretory cell
an animal cell that secretes mucous, such as in the nasal cavity
H
hamster
a small mammal that can be a pet or is used for experiments
heart
the organ in the body that pumps blood, that makes blood flow
heart attack
the heart stopping
A heart attack might kill cells in the heart.
A heart attack might also kill a person.
A big blood clot might cause a heart attack.
helper T cell (or: Th cell)
a T cell that helps other immune cells by making a kind of cytokine
hematology
science of how the blood works
herd immunity
the point during an epidemic when enough people have been
infected that on average each infected person passes the disease on
to at most one other person.
high blood pressure
when blood pushes harder on the walls of blood vessels
hormone
a substance produced in an organism (transported for example by the blood)
that sends a signal to cells to perform an action
horseshoe bat
a kind of bat
hospital
a center (a building) where doctors and nurses heal sick people
host cell
a cell (such as a human cell) in which a virus replicates
human (or: human being)
a person (Men and women are humans.)
hydrogen
one of the parts of the air around us
hydroxychloroquine
a drug that was made to treat malaria
hypothesis
(in science) a potential explanation based on observed evidence
hypoxia
a condition where tissue cells do not get all the oxygen they need
I
immune cell
any of several types of cells that are part of the immune system
immune signaling molecule
a molecule in the immune system that sends a signal
immune response
the defense reaction to foreign substances invading a body
immune system
our cells and molecules in our body that fight viruses
and other things that come into our body
immunity
the ability of a human or other organism to defend
against harmful substances
immunosuppressant drug
(or: immunosuppressive drug)
a drug that reduces the strength of the immune response
insect
a small living thing that flies or crawls, like an ant or other bugs
in vitro
taking place in the laboratory
in vivo
taking place inside a living thing
inconclusive (adjective)
still not certain
infect (verb)
to make a person or cells sick (A virus can infect people.)
infectious (adjective)
when a virus in a sick person can make another person sick
inflammation
when the immune system makes cells red, swollen and painful
inflammatory response
an immune response that causes tissue to become
red, swollen, hot and sometimes painful
interleukin
a type of glycoprotein and cytokine
produced by leukocytes (white blood cells)
that regulates immune responses
interferon
a signaling protein that tells nearby cells
to slow down the replication of a virus
intubation
insertion of a tube into the human body (such as into the lungs)
iron
a kind of metal
(Scientists sometimes write “Fe”, which means “iron”)
J
K
Kawasaki syndrome
a syndrome that causes inflammation in blood vessels throughout the body
kidneys
the two organs that process human waste into urine
killer T cell (or: cytotoxic T cell)
a type of white blood cell that (among other things) kills cells infected with a virus
L
leukocyte
lid
the cover of the toilet that can open or close
life
living things, things that are alive, that grow and that multiply
lungs
the container of the air we breathe into our body
(When we breathe, air goes into and out of our lungs.)
lupus
any one of several diseases that cause skin inflammation
lymphocyte
a type of small leukocyte (white blood cell) with a single round nucleus
M
maculopathy
any health condition of the macula, the part of the retina
in the eye at the center of the visual field
mammal
a kind of warm animal with hair or fur
Humans are mammals.
marker
a substance that when found in an organism
indicates a condition or situation in that organism
mask (or: face-mask)
(in the situation of a spreading viral disease) something worn over the face and nose
that filters droplets that may contain viruses
Masks are effective in preventing the spread of Covid-19.
matter
things that include what we can touch, smell or taste
medicine
something taken (usually by mouth) to treat a disease or condition
membrane
a thin wall such as a cell membrane or between the alveolus and capillaries
metabolize (verb)
to process by the natural chemical reactions in an organism
micro-clot (or: microclot)
a small blood clot
microbe
a microscopic organism
microscope
a device (a thing) used to see very small things
mink
a small mammal that is farmed for its fur
Some mink have caught Covid-19 from humans.
The mink seems to be the first mammal known to pass the disease back to humans.
misinformation
information that is totally or partially incorrect
model
a simplified mathematical description of a system
(usually a complex system) used for calculating,
such as for making predictions
molecule
the smallest part of most things that is still that thing
monoclonal antibodies
antibodies that are produced by immune cells that are
clones (identical copies) of the same cell
mucous (adjective)
about the mucus
mucus
liquid or thick matter that comes from the nose and is in the throat and lungs
When you have a cold, you have a lot of mucus in the nose.
When you cough, you cough out some mucus.
multiply
to make more living things
Humans multiply by having children.
multisystem inflammatory syndrome in children (MIS-C)
a condition, newly named by the CDC in the Covid-19 pandemic, of
inflammation in various organs that has appeared in children
mutate (verb)
to make a change in the genetic code
mutation
a change in the genetic code
myth
a false belief
N
nasal cavity
the space air flows through inside the nose
nature (or: natural world)
the observable universe, independent of the subjective human mind and human senses
necrosis
death of an organ or part of it
neutralize (verb)
(by an antibody) to block a virus from infecting a cell
neutralizing (adjective)
(of an antibody) able to block a virus from infecting a cell
neutralizing antibody
an antibody able to block a virus from infecting a cell
neutron
a thing in the middle of an atom, an atomic particle
novel
new
The novel coronavirus is a new kind of virus for people.
novel coronavirus
a new virus in people that is a kind of coronavirus
The novel coronavirus is a new kind of virus in people.
nucleotide (or: nucleotide base)
one unit (piece) of an RNA or DNA strand
nucleus, (more than one: nuclei)
an important part of a cell that looks like a smaller cell inside it
O
order of magnitude
about 10 times more or 10 times less
organ
(The heart and kidneys are organs.)
outlier
a person or thing that differs in some major way to the rest of a group
oxygen
a molecule of two atoms (O2) in the air we need to breathe in
oxygen saturation
the percentage of oxygen present in the red blood cells compared
to the total amount they can carry
P
pandemic
a disease spreading to many faraway places
pathologist
a health-care professional who studies diseased tissue
peer review
evaluation of a scientific article by someone in the same field
peptide
a chain of two or more amino acids
phosphorescence
the ability of atoms or molecules to produce light without heating up
placebo
a substance that looks like another drug but has no therapeutic effect
and serves as a control in drug trials
placebo effect
a benefit that only comes from the belief that a drug will be effective
plant
life that usually grows from the ground (Some plants have flowers.)
plasma
the colorless liquid part of blood
plasmid
RNA or DNA in the form of a ring (or other independent structure)
pneumocyte
one of two types of cells that line the alveoli
pneumonia
a lung inflammation from an infection that causes
the alveoli to fill with pus or become solid
polymerase
an enzyme that works to make copies of RNA or DNA
population
1: a community of humans or plant or animal species
2: collection of people, animals or things being studied
pre-print
an article that is available to read before it is officially published
presymptomatic (adjective)
describes an infected individual not yet appearing sick
pro-drug (or: prodrug)
a medication that is metabolized (processed chemically)
in the body to produce its active substance
projected
predicted according to a model
projection
a prediction based on a model
proof
evidence that establishes a fact
proof of concept
evidence that an idea has a good chance to be successful
protein
a big molecule created from RNA information
proton
a thing in the middle of an atom, an atomic particle
pulse oximeter
a device that measures oxygen in the blood
pus
a thick liquid in infected tissue containing dead
white blood cells, parts of dead cells, serum, etc.
Q
R
R number
a value that indicates, on the average, how many individuals
catch a disease from one infected individual
raw data
data that is collected but not yet processed
receptor
an enzyme on a cell membrane to which a virus can attach
red blood cell
the red cells in the blood that carry oxygen
remdesivir
a drug made by for treating Ebola (a disease)
replicate (verb)
to make copies of itself, to multiply
(A virus needs to find a cell so that it can replicate.)
(A virus replicates inside a host cell.)
rhesus macaque
a species of monkey (Macaca mulatta)
RNA
a special long molecule of information (RNA can get information from DNA.)
S
sac
a cavity enclosed by a membrane in a human or an organism
science
the systematic study of the natural world through observation and experiment
scientific evidence
evidence that supports or opposes a scientific theory or hypothesis
scientific method
the required way in which science advances
serological (adjective)
referring to the serum, and in particular to its immunological properties
serum
liquid that separates out from the blood when it coagulates
shed (verb)
to spread matter (such as mucous) with viruses inside
shock
a life-threatening drop in blood pressure
side effect
(of a drug) an undesirable, negative effect
signal protein
a protein, whose production or presence in the body
serves as a signal for a specific action
signaling molecule
a molecule, whose production or presence in the body
serves as a signal for a specific action
significant (adjective)
enough of a difference so that scientists do not think something happens just by chance
silent hypoxia
hypoxia unaccompanied by trouble breathing
social distance (verb)
to behave in a way that reduces the chance of spread of a disease in a population
social distancing (or: physical distancing)
behavior that reduces the chance of spread of a disease in a population
spike
1: a long thing on the outside of the virus that causes Covid-19
2: a very quick increase of something
spill over (verb)
(of a disease) to jump to another species
spillover
a jump of a disease between species, such as from a bat to humans
split
to break into two pieces, to divide into two
statin
a type of drug that reduces levels of fats
such as cholesterol and triglycerides in the blood
statistical (adjective)
related to statistics
statistics
mathematics that deals with collecting and analyzing a large amount of data
stools
solid waste from the human body
Stools go into the toilet.
stroke
brain tissue death from blood blocked by a blood clot
structural protein
a protein that can become a part of something in a cell
superspreader
an extraordinarily contagious individual in an epidemic
supply chain
the series of processes in the production and distribution of a product
swollen
made bigger
symptomatic
(of an infected individual) having symptoms of a disease,
appearing to be sick with a disease
synthesis
making a molecule from smaller molecules
synthesize (verb)
to make a molecule from smaller molecules
systemic reaction
a response, such as inflammation, that spreads to different organs
T
T cell
a type of lymphocyte that plays a major role in the immune system
tachycardia
(of the heart) an abnormally rapid pulse
testosterone
one of the male sex hormones, which sends
a signal in the body for the development of secondary sex characteristics
theory
a key hypothesis or a system of related and logically consistent hypotheses
therapeutic (adjective)
for healing
therapeutic drug
a drug designed for healing
thin (adjective)
(for the blood) that can flow (move) more easily
thrombotic (adjective)
related to thrombosis
thrombosis
blood coagulation or clotting
tissue
a part of a body made up of the same kinds of cells
TMPRSS2
an enzyme on the wall of some animal cells that
(possibly together with the furin enzyme) can cleave the SARS-CoV-2 spike,
which triggers a process to fuse the viral particle onto the cell membrane,
allowing the RNA to enter the host cell
tocilizumab
an immunosuppressant drug co-developed by Roche and Chugai Pharmaceutical
treat (verb)
to help stop a disease or to help someone feel better
trouble breathing
hard to breathe, difficult to breathe
type II pneumocyte
one of the types of cells on the inner lining of an alveolus,
which has the function of softening water so the alveolus does not collapse
U
urine
liquid human waste
Urine is the yellow liquid you “pee” into the toilet.
V
vaccine
a medicine that keeps a person from getting a disease
vaccine trial
testing of a vaccine in animals or in humans
variant
a form of a virus that is different because of a mutation
vascular (adjective)
relating to vessels, particularly blood vessels
ventilation
the supply of air by a ventilator
ventilator
a device that moves air into and out of the lungs
verify (verb)
(regarding science) to check that scientific work (such as the experiment)
is properly performed or the data used are valid
viral load
the number of viruses (viral particles) in a given amount of liquid
virion (or: viral particle)
the tiny virus, not the disease
virus
1: a very tiny thing that can get people sick (the viral particle)
2: the disease that the viral particle causes
W
wastewater
water made dirty by human use
Wastewater comes from toilets, bathrooms, washrooms, kitchens …
wet market
a marketplace that sells live animals for food
white blood cell
an important kind of immune cell in the blood
X
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©2020, 2021 Dr. Michael Herrera