Di-: Prefix taken directly from the Greek meaning twice or double or twofold, as in diacid, diamelia (absence of two limbs), diandry (double male genetic contribution) and digyny (double female genetic contribution); the drugs diazepam, dicyclomine (Bentyl), and diethylstilbestrol (DES); etc. Di- should not be confused with the prefix dia- which has a wholly different meaning.
