1rare The action or practice of reasoning by analogy; an instance of this. Compare "analogy".
historical, rare Mathematical proportion; a proportional.
historical Diagnosis or treatment of one disease by analogy with another.
Mid 17th century; earliest use found in Walter Charleton (1620–1707), physician and natural philosopher. From post-classical Latin analogismus and its etymon ancient Greek ἀναλογισμός proportionate calculation (from ἀναλογίζεσθαι to reckon up, sum up, to calculate, to consider from ἀνάλογος + -ίζεσθαι) + -ισμός.