LSJ
ὁ, mother΄s or father΄s brother, uncle, Eust. 971.26; but, mother΄s brother, Poll. 3.22, cf. IG 12(3).1628 (Thera), cj. in Epigr. ap. Plu. 2.1033e; or (in poetry), mother΄s father, Poll. 3.16 (v.l. νόννος); cf. νάννας, νίννη.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
Pape
ὁ, auch νάννος, Mutter- oder Vaterbruder, Oheim, Poll. 3.16, 22, Eust. 662.
Pape, Griechisch-deutsches Handwörterbuch (3. Aufl., 1914)