πλαγιοφύλαξ

A. guarding the flanks of an army on the march, ἶλαι π. D.S. 19.82 (v.l. πλαγιο‐φύλακοι) ; esp. of the corner man in the ῥόμβος (q.v.) of cavalry, Ascl. Tact. 7.2,6, Arr. Tact. 16.5 ; cf. πλαγυφύλαξ.