LSJ
ιος, ἡ, society of trustees for the care of a tomb, Petersen-Luschan Reisen in Lykien p. 22 n. 27 (Cyaneae), TAM 2 (1).62 (Telmessus); — hence μενδῖται, οἱ, members of such a society, ib. 40 (ibid.).
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)