James W. answered 06/03/19
Latin, Classical/NT Greek and literary Arabic tutor
Mos maiorum really means the "custom of the ancestors" - in other words traditional values and ways of doing things. Pietas, from which we get "piety" doesn't mean that in Classical Latin. It means having respect for and due observance of religious obligations. Lares familiares (not spelling) were household gods, minor deities whose statues were kept on the shelf and prayed to for assistance in domestic matters.