a combining form appearing in loanwords from French meaning "half" ( demilune ), "lesser" ( demitasse ), or sometimes used with a pejorative sense ( demimonde ); on this model, also prefixed to words of English origin ( demigod ).
[ demi (adj.; also n. and adv.) dimedius, for L dimidius half, equiv. to di- DI- 2 + medius middle ]