Early 17th century; earliest use found in Henry Cockeram (fl. 1623–1658), lexicographer. From classical Latin adaerātiōn-, adaerātiō calculation (of the area of a piece of land) (2nd cent. a.d. in texts on land surveying), in post-classical Latin also evaluation, payment from adaerāt-, past participial stem of adaerāre to calculate (the area of a piece of land) (2nd cent. a.d. in a text on land surveying), in post-classical Latin also to estimate, appraise, value + -iō.