bis-

Morpheme An occasional variant of bi- prefixed to roots beginning with a vowel, as in bisalternate

Chemistry, Natural sciences, Physical sciences Morpheme, 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)

Chemistry, Mathematics, Natural sciences, Physical sciences, Sciences Morpheme A variant of di-, used for substitutions of two complex rather than simple units.