Nitric oxide (NO) Nitric oxide (NO), colourless, toxic gas that is formed by the oxidation of nitrogen. Though it has few industrial applications, nitric oxide performs important chemical signaling functions in humans and other animals and has various applications in medicine.
or British mollusc /ËmÉËlÉsk/. plural mollusks. Learner's definition of MOLLUSK. [count] biology. : any one of a large group of animals (such as snails and clams) that have a soft body without a backbone and that usually live in a shell.
Hypernyms (mollusk is a kind of...): invertebrate (any animal lacking a backbone or notochord; the term is not used as a scientific classification). Meronyms (parts of mollusk): carapace; cuticle; shell; shield (hard outer covering or case of certain organisms such as arthropods and turtles).