(inorganic chemistry) The normal oxide of carbon, CO₂; a colorless, odorless gas formed during respiration and combustion and consumed by plants during photosynthesis.

(astronomy, physics) Either of two torus-shaped areas of high-energy charged particles which partly surround Earth, trapped by its magnetic field. The areas are characterised by intense radiation. ...

(UK, law) An adult, such as a parent, guardian, or social worker, whose role is to safeguard the interests of young people detained by the police, and who must be present at such interviews.

(informal, of a person) Being a motor mouth; inclined to talk too much.