pilgrim: [12] Etymologically, a pilgrim is someone who goes on a journey. The word comes via Provençal pelegrin from Latin peregrīnus ‘foreign’. This was a derivative of pereger ‘on a journey, abroad’, a compound formed from per ‘through’ and ager ‘country’ (source of English agriculture). When it arrived in English it was still being used for ‘traveller’ (a sense which survives in the related peregrinations [16]), but the specific ‘one who journeys for religious purposes’ was well established by the 13th century.
The peregrine falcon [14] got its name because falconers took its young for hunting while they were ‘journeying’ from their breeding places, rather than from their nests. => peregrine[pilgrim etymology, pilgrim origin, 英语词源]