This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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adj. Occurring every fourth day, counting inclusively, or every 72 hours. Used of a fever.

n. A malarial fever recurring every 72 hours.

n. A fever whose symptoms recur every four days.

adj. Recurring every four days; especially in designating a form of malaria with such symptoms.

adj. Of or pertaining to the fourth; occurring every fourth day, reckoning inclusively.

n. An intermittent fever which returns every fourth day, reckoning inclusively, that is, one in which the interval between paroxysms is two days.

n. A measure, the fourth part of some other measure.

Having to do with the fourth; especially, occurring every fourth day: as, a quartan ague or fever (one which recurs on the fourth day—that is, after three days).

n. An intermitting ague that occurs every fourth day, both days of consecutive occurrence being counted, as on Sunday, Wednesday, Saturday, Tuesday, etc.

n. A measure containing the fourth part of some other measure.

n. a malarial fever that recurs every fourth day

adj. occurring every fourth day (especially the fever and weakness of malaria)

"He admitted to having been laid low by a quartan ague but insisted it was nothing to worry about."

ague    chills and fever   

tertian    quotidian    paludal    dengue    ofgällivare    low-grade    lowish    endemial    nine-day    undulant