A pre-planned party in which participants secretively gather in a certain location, wait for the arrival of the person they wish to honour and, traditionally, greet the arrival of the honoured person by shouting, "Surprise!".

(UK politics) A centre-right political party, official full name Conservative and Unionist Party, informally known as the Tory Party. / (Canadian politics) Clipping of Progressive Conservative Party.

Removal of one's clothes while in a state of hypothermia.

A photon with a wavelength short enough to be considered a gamma ray, usually emitted from radioactivity.

The proposition in hydrostatics that any quantity of water, however small, may be made to counterbalance any weight, however great; or the law of the equality of pressure of fluids in all directions.

(politics) Within a legislative body, a member appointed by a political party and given the authority to ensure that all members of that party participate in voting and vote strictly as directed by the party in all votes where adherence to a party line is required.

(informal) To organize and execute a party.

An orgy.

A party, typically involving simple food, thrown in a cordoned-off street or road by its residents

(computing, programming, of a particular problem) Very easy to separate into a number of parallel tasks.