Anglicized form of Irish Gaelic Cinnéidigh. In recent years it has sometimes been used as a given name in the English-speaking world in honour of the assassinated American president John F. Kennedy (1917–63) and his brother Robert (1925–68).
English: 1. nickname from Middle English, Old French grace ‘charm’, ‘pleasantness’ (Latin gratia). 2. from the female personal name Grace, which was popular in the Middle Ages. This seems in the first instance to have been from a Germanic element grīs ‘gray’ (see Grice 1), but was soon associated by folk etymology with the Latin word meaning ‘charm’.