di-

Dia- Di"a-, Di- Di- . [Gr. dia` through; orig., dividing into two parts; akin to ? two. See {Two}, and cf. 1st {Di-}.] A prefix denoting through; also, between, apart, asunder, across. Before a vowel dia- becomes {di-}; as, diactinic; dielectric, etc. [1913 Webster]