bis-

Prefix

 * 1) An occasional variant of bi- prefixed to roots beginning with a vowel, as in bisalternate
 * 2)  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.
 * Bis (η6-arene) metal complexes have been made for many transition metals by the Al/AlCl3 reduction method.

Etymology 1
From.

Prefix

 * 1) ; ; di-
 * 2) great-
 * 1) great-

Etymology
From.

Prefix

 * 1) great-
 * 1) great-