antibodies: Any of a large number of proteins that the body produces from B cells and releases into the blood supply as part of its immune response. The production of antibodies is triggered when the body encounters an antigen, some foreign material. Antibodies then lock onto antigens as a first step in disabling the germs or other foreign substances that were the source of those antigens.
atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.
cell: The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell. (in telecommunications) A technology that relies on a large number of base stations to relay signals. Each base station covers only a small area, which is known as a cell. Phones that rely on this system are typically referred to as cell phones.
chronic: A condition, such as an illness (or its symptoms, including pain), that lasts for a long time.
electric charge: The physical property responsible for electric force; it can be negative or positive.
electron: A negatively charged particle, usually found orbiting the outer regions of an atom; also, the carrier of electricity within solids.
evaporate: To turn from liquid into vapor.
exotic: An adjective to describe something that is highly unusual, strange or foreign (such as exotic plants).
field: An area of study, as in: Her field of research was biology. Also a term to describe a real-world environment in which some research is conducted, such as at sea, in a forest, on a mountaintop or on a city street. It is the opposite of an artificial setting, such as a research laboratory. (in physics) A region in space where certain physical effects operate, such as magnetism (created by a magnetic field), gravity (by a gravitational field), mass (by a Higgs field) or electricity (by an electrical field).
fluorescent: (v. fluoresce) Adjective for something that is capable of absorbing and reemitting light. That reemitted light is known as fluorescence.
hormone: (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body. (in botany) A chemical that serves as a signaling compound that tells cells of a plant when and how to develop, or when to grow old and die.
immune: (adj.) Having to do with immunity. (v.) Able to ward off a particular infection. Alternatively, this term can be used to mean an organism shows no impacts from exposure to a particular poison or process. More generally, the term may signal that something cannot be hurt by a particular drug, disease or chemical.
immune system: The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.
infection: A disease that can spread from one organism to another. It’s usually caused by some type of germ.
ion: (adj. ionized) An atom or molecule with an electric charge due to the loss or gain of one or more electrons. An ionized gas, or plasma, is where all of the electrons have been separated from their parent atoms.
lightning: A flash of light triggered by the discharge of electricity that occurs between clouds or between a cloud and something on Earth’s surface. The electrical current can cause a flash heating of the air, which can create a sharp crack of thunder.
liquid: A material that flows freely but keeps a constant volume, like water or oil.
liver: An organ of the body of animals with backbones that performs a number of important functions. It can store fat and sugar as energy, break down harmful substances for excretion by the body, and secrete bile, a greenish fluid released into the gut, where it helps digest fats and neutralize acids.
magnetic field: An area of influence created by certain materials, called magnets, or by the movement of electric charges.
matter: Something that occupies space and has mass. Anything on Earth with matter will have a property described as "weight."
molecule: An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).
nutrient: A vitamin, mineral, fat, carbohydrate or protein that a plant, animal or other organism requires as part of its food in order to survive.
particle: A minute amount of something.
physics: The scientific study of the nature and properties of matter and energy. Classical physics is an explanation of the nature and properties of matter and energy that relies on descriptions such as Newton’s laws of motion. Quantum physics, a field of study that emerged later, is a more accurate way of explaining the motions and behavior of matter. A scientist who works in such areas is known as a physicist.
plasma: (in chemistry and physics) A gaseous state of matter in which electrons separate from the atom. A plasma includes both positively and negatively charged particles. (in medicine) The colorless fluid part of blood.
platelets: The smallest of blood cells, their role is to hunt for signs that a blood vessel has been damaged. Then the platelets congregate at the site of damage and transform themselves, growing long tentacles. There, they link together, creating a clot to plug any hole. This should help stem the potential loss of blood.
protein: A compound made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. Among the better-known, stand-alone proteins are the hemoglobin (in blood) and the antibodies (also in blood) that attempt to fight infections. Medicines frequently work by latching onto proteins.
red blood cell: Colored red by hemoglobin, these cells move oxygen from the lungs to all tissues of the body. Red blood cells are too small to be seen by the unaided eye.
solar: Having to do with the sun or the radiation it emits. It comes from sol, Latin for sun.
solar wind: A flow of charged particles (including atomic nuclei) that have been ejected from the surface of the star, such as our sun. It can permeate the solar system. This is called a stellar wind, when from a star other than the sun.
solid: Firm and stable in shape; not liquid or gaseous.
star: The basic building block from which galaxies are made. Stars develop when gravity compacts clouds of gas. When they become hot enough, stars will emit light and sometimes other forms of electromagnetic radiation. The sun is our closest star.
sun: The star at the center of Earth’s solar system. It is about 27,000 light-years from the center of the Milky Way galaxy. Also a term for any sunlike star.
universe: The entire cosmos: All things that exist throughout space and time. It has been expanding since its formation during an event known as the Big Bang, some 13.8 billion years ago (give or take a few hundred million years).
vitamin: Any of a group of chemicals that are essential for normal growth and nutrition and are required in small quantities in the diet because either they cannot be made by the body or the body cannot easily make them in sufficient amounts to support health.
white blood cells: Blood cells that help the body fight off infection.
