Latinate name, first used by Shakespeare for the rich heiress wooed by the duke in Twelfth Night (1599). Shakespeare may have taken it as a feminine form of Oliver or he may have derived it from Latin oliva ‘olive’. In the 1970s it was particularly associated with the Australian pop singer and actress Olivia Newton-John (b. 1948). Since the 1990s it has been very popular throughout the English-speaking world.
Spanish (García) and Portuguese: from a medieval personal name of uncertain origin. It is normally found in medieval records in the Latin form Garsea, and may well be of pre-Roman origin, perhaps akin to Basque (h)artz ‘bear’.