Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Trans- \Trans-\ [L. trans across, over.] A prefix, signifying over, beyond, through and through, on the other side, as in transalpine, beyond the Alps; transform, to form through and through, that is, anew, transfigure.
Douglas Harper's Etymology Dictionary
word-forming element meaning "across, beyond, through, on the other side of, to go beyond," from Latin trans-, from trans (prep.) "across, over, beyond," perhaps originally present participle of a verb *trare-, meaning "to cross," from PIE *tra-, variant of root *tere- (2) "to cross over" (see through). In chemical use indicating "a compound in which two characteristic groups are situated on opposite sides of an axis of a molecule" [Flood].
Wiktionary
pre. 1 across, through, over, beyond, to or on the other side of, outside of 2 (context chemistry English) a compound in which two atoms or groups are situated on opposite sides of some plane of symmetry passing through the compound 3 transgender or transsexual, or pertaining to those who are transgender or transsexual