[1840–50; bi-1 + millenary]This word is first recorded in the period 1840–50. Other words that entered Englishat around the same time include: creationism, dope, layout, plaque, set piecebi- is a combining form meaning “twice,” “two,” used in the formation of compound words.Other words that use the affix bi- include: biceps, bilateral, bimodal, bipolar, bivalent