Late 16th century; earliest use found in Thomas Nashe (d. c1601), writer. From classical Latin prō ārīs et focīs, lit. ‘for altars and hearths’ from prō + ārīs, ablative plural of āra altar + et and + focīs, ablative plural of focus hearth, fireplace, sacrificial hearth.
Definition of pro aris et focis in US English:
pro aris et focis
adverbˌprəʊ ˈɑːriːs ɛt ˈfəʊkiːs
On behalf of religion and domestic life.
Origin
Late 16th century; earliest use found in Thomas Nashe (d. c1601), writer. From classical Latin prō ārīs et focīs, lit. ‘for altars and hearths’ from prō + ārīs, ablative plural of āra altar + et and + focīs, ablative plural of focus hearth, fireplace, sacrificial hearth.