early 15c., patricion, "member of the ancient Roman noble order," reputed descendants of the original citizens, from Old French patricien, from Latin patricius "of the rank of the nobles, of the senators; of fatherly dignity," from patres conscripti "Roman senators," from plural of pater "father" (see father (n.)).
In ancient Rome, contrasted with the plebeius (see plebeian). In post-classical times, applied to noble citizens and higher orders of free folk in medieval Italian and German cities (a sense attested in English from 1610s); hence "nobleman, aristocrat" in a modern sense (1630s). As an adjective, attested from 1610s, from the noun. Related: Patricianism.