LSJ
ακος, ὁ, curator of boundary-stones, GDI 5653 A 15 (Chios, v BC, prob. in Ion. form οὐρο-).
frontier-guard, PSI 4.406.12 (iii BC), SIG 633.89 (Milet., ii BC).
preserving limits, τινων Procl. in Ti. 3.184 D.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)