Late 19th century; earliest use found in The New Sydenham Society's Lexicon of Medicine and the Allied Sciences. From post-classical Latin anemius (1506 or earlier; from Hellenistic Greek ἀνέμιος, variant reading for ancient Greek ἀνέμαῖος windy, empty, vain (from ἄνεμος wind + -αῖος, suffix forming adjectives)) + -ous.