ἰλ-άρχης · il-archēs — LSJ
commander of a troop of horse
commander of a troop of horse, PPetr. 3p.8 (iii B.C.), al., Ascl. Tact. 7.2, Plu. Tim. 31 (pl.), Arr. An. 2.7.3; = Lat. praefectus turmae, Plb. 6.25.1, 6.35.8.
II commander of eight elephants, command cavalry
commander of eight elephants, Ascl. Tact. 9, Ael. Tact. 23:— hence ἰλ-αρχέω, Boeot. ϝιλαρχίω, command cavalry, IG 7.3087 (Lebad.), 3206 (Orchom.), 2466 (Thebes).
II to be sevir equitum
at Rome, to be sevir equitum, D.C. 55.10.