γραμμᾰτ-ιστής · grammat-istēs — LSJ
= γραμματεύς, clerk, registrar, Hdt. 2.28, 3.123, IG 7.1745 (Thespiae), SIG 529.4 (Dyme, iii B. C.), etc.: metaph., recorder, of memory (cf. γραμματεύς 2), Pl. Phlb. 39b.
one who teaches γράμματα, elementary schoolmaster, X. Smp. 4.27, Pl. Prt. 312b, al., D. 19.281, D.H. 11.28, Diog.Oen. 11, etc.