Late Middle English; earliest use found in Geoffrey Chaucer (c1340–1400), poet and administrator. From (i) post-classical Latin porisma a deduction, a corollary and its etymon (ii) Hellenistic Greek πόρισμα a deduction from a previous demonstration, a corollary (Euclid), a kind of proposition intermediate between a theorem and a problem from ancient Greek πορίζειν to carry, to provide, in Hellenistic Greek also to find out +-μα.