late 13c., "to rule with authority," from Old French governer "steer, be at the helm of; govern, rule, command, direct" (11c., Modern French gouverner), from Latin gubernare "to direct, rule, guide, govern" (source also of Spanish gobernar, Italian governare), originally "to steer, to pilot," a nautical borrowing from Greek kybernan "to steer or pilot a ship, direct as a pilot," figuratively "to guide, govern" (the root of cybernetics). The -k- to -g- sound shift is perhaps via the medium of Etruscan. Intransitive sense from 1590s. Related: Governed; governing.

1734, formed in American English from Latin gubernator "a governor" (see govern) + -al (1). OED marks it "Chiefly U.S.," and Century Dictionary says "Chiefly in newspaper use." As English words, gubernator was in use from 1520s, gubernation from mid-15c., but both are rare.

English agent noun ending, corresponding to Latin -or. In native words it represents Old English -ere (Old Northumbrian also -are) "man who has to do with," from Proto-Germanic *-ari (cognates: German -er, Swedish -are, Danish -ere), from Proto-Germanic *-arjoz. Some believe this root is identical with, and perhaps a borrowing of, Latin -arius (see -ary).

Generally used with native Germanic words. In words of Latin origin, verbs derived from past participle stems of Latin ones (including most verbs in -ate) usually take the Latin ending -or, as do Latin verbs that passed through French (such as governor); but there are many exceptions (eraser, laborer, promoter, deserter; sailor, bachelor), some of which were conformed from Latin to English in late Middle English.

The use of -or and -ee in legal language (such as lessor/lessee) to distinguish actors and recipients of action has given the -or ending a tinge of professionalism, and this makes it useful in doubling words that have a professional and a non-professional sense (such as advisor/adviser, conductor/conducter, incubator/incubater, elevator/elevater).

mid-15c., "female ruler," shortening of governouresse "a woman who rules" (late 14c.), from Old French governeresse "female ruler or administrator" (see governor + -ess). The Latin fem, form was gubernatrix. In the sense of "a female teacher in a private home" governess it is attested from 1712, probably as a fem. of governor in the now-obsolete sense "one who has charge of a young man's education and activities, a tutor" (1570s).

1890, shortening of guvner, casual British pronunciation of governor as a title of respect.