As noted in LSJ s.v., this headword appears only in lexica and grammars as a word in its own right; elsewhere it is a suffix; in the Suda see e.g. alpha 786, beta 38, epsilon 3681.
Similarly glossed in ps.-Zonaras, and (according to Adler) in the Ambrosian Lexicon; see also Etymologicum Magnum 703-11-12.