An area in the Atlantic Ocean where many ships and planes have disappeared under allegedly mysterious circumstances.

(mathematics) A geometric representation of the binomial coefficients in a triangle, each entry being the sum of the two entries above.

Used other than figuratively or idiomatically: see black, triangle. / (ufology) One of a class of triangle-shaped unidentified flying objects, usually with a light in each corner.

(anatomy) An anatomic space bordered by the common hepatic duct, the cystic duct and base of the liver. It is used to identify the cystic artery.

plural of triangle wave

(mathematics, engineering) A function or waveform that alternately ramps linearly upwards and then downwards.

(idiomatic) A relationship involving three persons (usually two women and one man or two men and one woman) among whom there are conflicting and competing attachments of a romantic or emotional nature.

(historical) A key communist Chinese and North Korean concentration area and communications junction during the Korean War, located in the central sector.

(US politics, political science) The policy-making relationship among the congressional committees, the bureaucracy (executive, sometimes called “government agencies”), and interest groups or lobbyists.

(derogatory, dated) A Jehovah's Witness. / (historical) A Jehovah's Witness in Nazi Germany.