What is the Latin word for quartan?

The usual Latin words for “quartan” are quārtus, quārtānus. The right choice depends on the sense; see the distinctions below.

English → Latin

“quartan” in Latin

quārtusfourth quārtānusfourth (e.g. on the fourth day, of the fourth legion etc.)

The English word quartan itself goes back to Latin quārtus, through quartāna.

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

quartan

quartus: a quartan fever, (febris) quartana; febris quadrini circuitus (Plin.); quartis diebus recurrens.

Quick answer

What is the Latin word for quartan?: The usual Latin words for “quartan” are quārtus, quārtānus. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.