- aff. a combining form meaning “twice,”“two”bicarbonate.•Etymology: < L; cf. twi- usage: Most words referring to periods of time and prefixed by bi- are potentially ambiguous. Since bi- can be taken to mean either “twice each” or “every two,” a word like biweekly can be understood as “twice each week” or “every two weeks.” Confusion is often avoided by using the prefix semi- meaning “twice each” (semiweekly; semimonthly; semiannual) or by using the appropriate phrases: twice a week; twice each month; every two months; every two years. IIbi-aff. var. of bio-, esp. before a vowel:biopsy[/ex]
From formal English to slang. 2014.