Origin and history of trans

1570s, in grammar, of verbs, "taking a direct object," 1570s (implied in transitively), from Late Latin transitivus (Priscian) "transitive," literally "passing over (to another person)," from transire "cross over, go over, pass over, hasten over, pass away," from trans "across, beyond" (see trans-) + ire "to go" (from PIE root *ei- "to go").

In the general sense of "having the power of passing into something, characterized by or involving transition" in any sense, by 1610s. As a noun, "a transitive verb," by 1610s. Related: Transitiveness; transitivity.

word-forming element meaning "across, beyond, through, on the other side of; go beyond," from Latin trans (prep.) "across, over, beyond," perhaps originally present participle of a verb *trare-, meaning "to cross," from PIE *tra-, variant of root *tere- (2) "cross over, pass through, overcome" [Watkins].

Besides its use in numerous English words taken from Latin words with this prefix, it is used to some extent as an English formative .... It is commonly used in its literal sense, but also as implying complete change, as in transfigure, transform, etc. [Century Dictionary]

In chemical use indicating "a compound in which two characteristic groups are situated on opposite sides of an axis of a molecule" [Flood].

Many trans- words in Middle English via Old French arrived originally as tres-, due to sound changes in French, but most English spellings were restored later; trespass and trestle being exceptions.