mid-15c., from L. educatus, pp. of educare "bring up, rear, educate," which is related to educere "bring out," from ex- "out" + ducere "to lead" (see duke). Meaning "provide schooling" is first attested 1588 in Shakespeare.
pp. adj. from educate. As an abbreviated way to say well-educated, attested from 1855. Educated guess first attested 1954.