Definition of onomasticon in English:

onomasticon

noun

  • A vocabulary or lexicon of (especially personal) proper names, usually presented in alphabetical order. In early use also: a list of nouns; a lexicon.

Origin

Early 18th century. From Hellenistic Greek ὀνομαστικόν book of names, vocabulary, use as noun (short for ὀνομαστικόν βιβλίον) of neuter singular of ancient Greek ὀνομαστικός onomastic.

Pronunciation

onomasticon

/ˌɒnəˈmastɪkɒn/