cus·tos \ˈkəˌstäs, -tōs; ˈku̇ˌstōs, ˈküˌ-\noun (pluralcus·to·des \(ˌ)kəˈstō(ˌ)dēz; ku̇ˈstōˌdās, kü-\) Etymology: Middle English, guardian, from Latin — more at custody 1.: keeper, custodian, guard 2.: direct 1 3.[Medieval Latin, from Latin]: a superior of a Franciscan province or custody