(idiomatic) a pessimistic person who sees possible calamity in every situation.

(medicine) A form of prevention, usually medication, taken after exposure (or probable exposure) to a pathogen, preventing development of disease after such exposure; especially, as against HIV.

(medicine) A form of prevention, usually medication, that is taken before exposure to a pathogen, preventing development of disease after such exposure. Especially:

analogy between four things, in which A is to B as C is to D, or A : B = C : D.

(rare) The quality of being a proper noun.

(idiomatic) An idea which is especially extreme, unorthodox or distasteful, often put forward in jest. / Used other than figuratively or idiomatically: see modest, proposal.

False or unverified propaganda, especially appearing to come from an enemy's own sources; disinformation.

(dated) plural of mean proportional

The geometric mean.

(law) Intellectual property as used in commerce and industry, particularly patents and trademarks, as distinguished in some European legal systems from intellectual property as used in the arts.