LSJ
ωνος, ὁ, = Lat. tiro, recruit, PSI 9.1063.5, 25 (ii AD); written τείρων ib. 12; found mostly in gen. pl. ; the dat. pl. τιρόναις BGU 21 ii 11, iii 4 (iv AD) points to nom. sg. τιρόνης (τιρώνης).
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)