Defn: A discourse or treatise on fevers; the doctrine of fevers.
Hooper.

PYREXIA
Py*rex"i*a, n.; pl. Pyrexiæ. Etym: [NL., fr. Gr. (Med.)

Defn: The febrile condition.

PYREXIAL; PYREXICAL
Py*rex"i*al, Py*rex"ic*al, a. (Med.)

Defn: Of or pertaining to fever; feverish.

PYRGOM
Pyr"gom, n. Etym: [Gr. (Min.)

Defn: A variety of pyroxene; — called also fassaite.

PYRHELIOMETER
Pyr*he`li*om"e*ter, n. Etym: [Gr. -meter.] (Physics)

Defn: An instrument for measuring the direct heating effect of the sun's rays.

PYRIDIC
Py*rid"ic, a. (Physiol. Chem.)