noun: (business) A deal to swap goods or services.
noun: (politics, derogatory) A conservative; originally tied to Nicaraguan counter-revolutionaries.
noun: (accounting, often attributive) An entry (or account) that cancels another entry (or account).
noun: (music, informal) Any of the musical instruments in the contrabass range, e.g. contrabassoon, contrabass clarinet or, especially, double bass.
noun: (dance) A contra dance.
noun: (obsolete, US, New England, dance) A country dance.
verb: (accounting) To undo; to reverse.
noun: A member of any of various rightist guerrilla groups violently opposing the socialist Sandinista government of Nicaragua and secretly funded by the United States government in the 1980s.