1900, as Ping-Pong, trademark for table tennis equipment (Parker Brothers). Both words are imitative of the sound of the ball hitting the paddle; from ping (q.v.) + pong, attested from 1823. The verb is from 1901; in the figurative sense, 1952.
architecture A phenomenon which can occur in a multi-processor system with private caches where two processors are alternately caching a shared location. Each time one writes to it, it invalidates the other's copy. (1995-12-29)