Quartaine

Part of speech: noun

Definitions

1. An obsolete term for a fever that returns at intervals of three days, so that each attack falls on every fourth day
2. A historical name for a malarial-type illness that recurs every fourth day, with symptoms flaring up roughly every three days in between
3. An archaic medical label for a periodic fever whose fits come back on a cycle counted as every fourth day

Etymology: In French, "quartaine" is the adjective in "fièvre quartaine," the fever that recurs every fourth day, which is the same idea as the English "quartan" fever. The root is the Latin "quartus," "fourth," and the Latin "quartanus" was used in the same medical sense. The French form shows the usual Latin-to-French shift, with the Latin ending becoming "-aine."