[1645–55; tri- + partition]This word is first recorded in the period 1645–55. Other words that entered Englishat around the same time include: complex, cruise, herringbone, revival, simmertri- is a combining form meaning “three,” used in the formation of compound words. Otherwords that use the affix tri- include: triforium, triglyceride, trilemma, triple, trivial