co-education n.

in Latin, the form of com- "together, with" in compounds with stems beginning in vowels, h-, and gn-; see com-. Taken in English from 17c. as a living prefix meaning "together, mutually, in common," and used promiscuously with native words (co-worker) and Latin-derived words not beginning with vowels (codependent), including some already having it (co-conspirator).

1530s, "child-rearing," also "the training of animals," from French education (14c.) and directly from Latin educationem (nominative educatio) "a rearing, training," noun of action from past-participle stem of educare (see educate). Originally of instruction in social codes and manners; meaning "systematic schooling and training for work" is from 1610s.

All education is despotism. [William Godwin, "Enquirer," 1797] 

also coeducational, "involving or pertaining to joint education of men and women at the same institution," 1868, from co-education + -al (1).