Definition of -onym in English:

-onym

combining form

  • 1Forming nouns.

    1. 1.1Denoting a type of name.
      ‘pseudonym’
    2. 1.2Denoting a word having a specified relationship to another.
      ‘antonym’

Origin

From Greek -ōnumon, neuter of -ōnumos, combining form of onoma name.