κατήχ-ησις · katēch-ēsis — LSJ
instruction by word of mouth, instruction, communication
instruction by word of mouth: generally, instruction, Hp. Praec. 13, Cic. Att. 15.12.2, D.H. Dem. 50, Din. 7, Ath.Med. ap. Orib. inc. 21.6, S.E. M. 1.7; διὰ τὴν κ. τῶν συνόντων by communication with companions, in bad sense, Chrysipp.Stoic. 3.54, cf. 55, Gal. 5.463.
II accompaniment, which drown
accompaniment of the monochord by louder instruments which drown its tune, Ptol. Harm. 2.12 (pl.).