1660s, past-participle adjective from educate (v.). As an abbreviated way to say well-educated, attested from 1855. Educated guess first attested 1954.
mid-15c., educaten, "bring up (children), to train," from Latin educatus, past participle of educare "bring up, rear, educate" (source also of Italian educare, Spanish educar, French éduquer), which is a frequentative of or otherwise related to educere "bring out, lead forth," from ex- "out" (see ex-) + ducere "to lead," from PIE root *deuk- "to lead." Meaning "provide schooling" is first attested 1580s. Related: Educated; educating.
According to "Century Dictionary," educere, of a child, is "usually with reference to bodily nurture or support, while educare refers more frequently to the mind," and, "There is no authority for the common statement that the primary sense of education is to 'draw out or unfold the powers of the mind.'"
1660s, of persons, "cultured, refined, educated;" 1797, of land, "subject to cultivation;" past-participle adjective from cultivate (v.).
"educated, instructed, having knowledge of letters," early 15c., from Latin literatus/litteratus "educated, learned, who knows the letters;" formed in imitation of Greek grammatikos from Latin littera/litera "alphabetic letter" (see letter (n.1)). By late 18c. especially "acquainted with literature." As a noun, "one who can read and write," 1894.