Early 17th century; earliest use found in John Deacon (fl. 1585–1616). From ancient Greek αἴσθησις sense perception, sensation, perception from the stem of αἰσθάνεσθαι to perceive (probably from the same base as ἀίειν to perceive, hear from the same Indo-European base as Sanskrit āvis-, Avestan āviš manifestly, Old Church Slavonic avě openly) + -σις.