governess n.

c. 1300, gouernour, "personal keeper, protector, guide;" late 14c., "one who governs, a ruler," from Old French governeor "prince, ruler, administrator; helmsman" (11c., Modern French gouverneur) and directly from Latin gubernatorem (nominative gubernator) "director, ruler, governor," originally "steersman, pilot" (see govern). Meaning "subordinate ruler; head of a province, etc." is from late 14c. Meaning "one charged with direction or control of an institution, etc." is from late 14c. Mechanical sense of "self-acting regulator" is from 1819. The adjective gubernatorial remembers the Latin form. There is a record of English governator from 1520s.

fem. suffix, from French -esse, from Late Latin -issa, from Greek -issa (cognate with Old English fem. agent suffix -icge); rare in classical Greek but more common later, in diakonissa "deaconess" and other Church terms picked up by Latin.