What is the origin of onomastic?
English onomastic comes straight from the Greek adjective and noun onomastikós, which has quite a few meanings: “pertaining to a name, naming, special name; (in grammar) nominative (case); vocabulary (organized by subject and not by letter).” Onomastikós is a derivative of the verb onomázein “to name, call by name,” itself a derivative of the noun ónoma, the Greek development of Proto-Indo-European nomen-, which appears in Latin as nōmen, Germanic (English) name, and Sanskrit nā́ma. One of the things that make Greek Greek is the presence of prothetic vowels (prothetic means “put in front”) at the beginning of a word, such as the o- in ónoma, the a- in ástron “star” (akin to English star and Latin stella, from assumed sterla), the e- in ennéa “nine” (Latin novem, Sanskrit náva). Some of the prothetic vowels can be explained according to Indo-European linguistics, others not; they are a source of endless research and speculation. Onomastic entered English in the 18th century.