The Spanish word 'peregrino' meaning 'pilgrim' or 'traveler' comes from the Latin word 'peregrinus', which meant 'foreigner' or 'traveler'. The Latin word itself was formed by combining two elements: the prefix 'per-' meaning 'through' and 'ager' meaning 'field' or 'land'. So etymologically, a 'peregrino' was someone who went through or across lands - essentially, a traveler or wanderer.

A related Spanish word is 'peregrinación' meaning 'pilgrimage', and the verb 'peregrinar' meaning 'to pilgrim' or 'to wander'. These words share the same Latin root and maintain the core concept of traveling or journeying.

The English word 'pilgrim' is actually a cousin of 'peregrino', as it also derives from Latin 'peregrinus', though it came through Old French. Another related English word is 'peregrinate' meaning 'to travel or wander around', which is a more direct borrowing from Latin. The word 'peregrine' as in 'peregrine falcon' also comes from this same root - it was so named because young falcons were captured during their migration (their travels) rather than taken from nests.