I. ˈkwȯr-t ə n adjective
Etymology: Middle English quarteyn, from Anglo-French ( fevre ) quartaine quartan fever, from Latin ( febris ) quartana, from quartanus of the fourth, from quartus
Date: 14th century
: occurring every fourth day reckoning inclusively ; specifically : recurring at approximately 72-hour intervals
a quartan ague
II. noun
Date: 14th century
: a quartan fever