travel

[14] Travel and travail [13] are doublets – that is to say, they have a common ancestor, but have split into separate words. Their ultimate source is medieval Latin trepālium, a term for an instrument of torture made of three sharp stakes. This was a compound noun formed from Latin trēs ‘three’ and pālus ‘stake’ (source of English pale). From it was formed a verb *trepāliāre ‘torture on the trepālium’, hence generally ‘torture’. This passed into Old French as travailler, where its reflexive use ‘put oneself to pain or trouble’ evolved to ‘work hard’. Its noun derivative travail ‘painful effort, hard work’ was borrowed by English as travail, and this quickly developed a new sense, ‘journey’ (presumably from the notion of a ‘wearisome journey’), which came to be distinguished by the spelling travel. => PALE, THREE, TRAVAIL

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   The verb meaning 'journey' developed from the verb travail, meaning 'labor,' the concept being that a journey is a laborious business, one requiring effort and possibly discomfort. Travail itself derives from Old French travaillier (compare modern French travailler, 'to work'), in turn from a conjectured Vulgar Latin verb tripaliare, 'to torture,' formed from the Late Latin noun trepalium. This was an instrument of torture constructed from three stakes, and itself represents a blend of Latin tres, 'three,' and palus, 'stake.'