Look up Hilary in Wiktionary, the free dictionary.
Hilary or Hillary is a given and family name, derived from the Latinhilarius meaning "cheerful", from hilaris, "cheerful, merry" which comes from the Greek ἱλαρός (hilaros), "cheerful, merry", which in turn comes from ἵλαος (hilaos), "propitious, gracious". Historically (in America), the spelling Hilary has generally been used for men and Hillary for women, though there are exceptions, some of which are noted below. In modern times it has drastically declined in popularity as a name for men. Ilaria is the popular Italian and Spanish feminine form, while Ilario is the Italian masculine one. Ilariana and Ylariana (/aɪˌlɑːriˈɑːnə/eye-LAH--ree-AH-nə) are two very rare feminine variants of the name.