late 14c., "to journey," from travailen (1300) "to make a journey," originally "to toil, labor" (see travail). The semantic development may have been via the notion of "go on a difficult journey," but it also may reflect the difficulty of any journey in the Middle Ages. Replaced Old English faran. Related: Traveled; traveling. Traveled (adj.) "having made journeys, experienced in travel" is from early 15c. Traveling salesman is attested from 1885.
late 14c., "action of traveling," from travel (v.). Travels "accounts of journeys" is recorded from 1590s. Travel-agent is from 1925.