1. a prefix occurring in loanwords from Latin ( transcend; transfix ); on this model, used with the meanings "across," "beyond," "through," "changing thoroughly," "transverse," in combination with elements of any origin: transisthmian; trans-Siberian; transempirical; transvalue.
2. Chem. a prefix denoting a geometric isomer having a pair of identical atoms or groups on the opposite sides of two atoms linked by a double bond. Cf. cis- (def. 2).
3. Astron. a prefix denoting something farther from the sun (than a given planet): trans-Martian; trans-Neptunian.
[ trans (adv. and prep.) across, beyond, through ]