preposition

From Middle English preposicioun, from Old French preposicion, from Latin praepositio, from praepono, meaning 'to place before' — a combination of pre- and position.

Latin grammarians named it for exactly what it does: it's placed before the word it's phrased with, as in 'a bridge of iron' or 'he comes from town.' The name has stuck to that same positional job ever since.

It shares its Latin roots with the English word 'position,' since praepositio is literally 'pre-' plus 'position.'