The Spanish word 'celibato' (meaning 'celibacy') comes from the Latin word 'caelibatus', which meant 'the state of being unmarried'. This Latin word was derived from 'caelebs', meaning 'unmarried or single'. The evolution from Latin to Spanish mainly involved the softening of the 'ae' sound to 'e' and standardizing the ending to '-ato', which is a common pattern in Spanish words derived from Latin.

A related Spanish word is 'célibe', which means 'celibate' or 'unmarried'. Both 'celibato' and 'célibe' share the same Latin root and maintain similar meanings related to being unmarried, though 'celibato' specifically refers to the state or practice of celibacy, while 'célibe' describes a person who is celibate.

The English word 'celibate' and 'celibacy' are direct cognates of the Spanish 'celibato', as they all derive from the same Latin roots. These words have maintained their original meaning relating to the state of being unmarried, though in modern usage they often specifically refer to abstaining from marriage and sexual relations, especially for religious reasons.