quintan
/ˈkwɪntən/Medicine
noun
A fever that recurs (by inclusive reckoning) every fifth day. Now historical and rare.
adjective
Recurring (by inclusive reckoning) every fifth day (i.e. at intervals of approximately ninety-six hours); specifically designating fever (in later use especially trench fever) which recurs in this way.
Origin
Early 17th century; earliest use found in Philemon Holland (1552–1637), translator. From French quintane, adjective or its etymon post-classical Latin quintana (in febris quintana fever that occurs every fifth day) from classical Latin quīntāna, feminine of quīntānus of or relating to the fifth from quīntus fifth + -ānus. Compare ancient Greek πεμταῖος, short for πεμταῖος πυρετός quintan fever. Compare also Spanish quintana, noun, fiebre quintana, Italian quintana, noun, and Middle French, French fièvre quinte.