co-educational (adj.)

also coeducation, "joint education," specifically of young men and young women in the same institution, 1852, from co- + education.

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).

also coed, 1886, American English, (first in Louisa Mae Alcott's "Jo's Boys"); short for "co-educational system;" 1889 as an adjective, short for co-educational; 1887 as a noun meaning "girl or woman student at a co-educational institution."