[1855–60; bi-1 + flagellate]This word is first recorded in the period 1855–60. Other words that entered Englishat around the same time include: barrage, keyword, lavabo, specialist, superheatbi- is a combining form meaning “twice,” “two,” used in the formation of compound words.Other words that use the affix bi- include: bilateral, bilingual, bipolar, bisect, bivalent