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.
Mollusks are soft-bodied animals often covered by hard shells. This group of invertebrates includes a variety of animals; snails, clams, and octopus are the most common. There â¦ are more than 85,000 species of mollusks and there is believed to be many more that haven't been identified.ny of numerous chiefly marine invertebrates of the phylum Mollusca, typically having a soft unsegmented body, a mantle, and a protective calcareous shell and including the ed â¦ ible shellfish and the snails.