bis-

Meaning

1. An occasional variant of bi- prefixed to roots beginning with a vowel, as in bisalternate
2. (obsolete) A variant of di- used to indicate that the component that does not take the prefix occurs twice in the compound: a bisoxide is of the form B₂O (cf. dioxide for XO₂)
3. A variant of di-, used for substitutions of two complex rather than simple units.

Synonyms

bi-

bis

di

di-