Pyrheliometer
(Pyr*he`li*om"e*ter) n. [Gr. fire + sun + -meter.] (Physics) An instrument for measuring
the direct heating effect of the sun's rays.
Pyridic
(Py*rid"ic) a. (Physiol. Chem.) Related to, or formed from, pyridin or its homologues; as, the
pyridic bases.
Pyridine
(Pyr"i*dine) n. [From Gr. fire.] (Physiol. Chem.) A nitrogenous base, C5H5N, obtained from
the distillation of bone oil or coal tar, and by the decomposition of certain alkaloids, as a colorless liquid
with a peculiar pungent odor. It is the nucleus of a large number of organic substances, among which
several vegetable alkaloids, as nicotine and certain of the ptomaïnes, may be mentioned. See Lutidine.
Pyridyl
(Pyr"i*dyl) n. [Pyridine + -yl.] (Chem.) A hypothetical radical, C5H4N, regarded as the essential
residue of pyridine, and analogous to phenyl.
Pyriform
(Pyr"i*form) a. [L. pyrum, pirum, a pear + -form: cf. F. pyriforme, piriforme.] Having the
form of a pear; pear- shaped.
Pyritaceous
(Pyr`i*ta"ceous) a. (Min.) Of or pertaining to pyrites. See Pyritic.
Pyrite
(Pyr"ite) n.; pl. Pyrites [Cf. F. pyrite. See Pyrites.] (Min.) A common mineral of a pale brass-
yellow color and brilliant metallic luster, crystallizing in the isometric system; iron pyrites; iron disulphide.
Hence sable coal his massy couch extends,
And stars of gold the sparkling pyrite blends.
E. Darwin. Pyrites
(Py*ri"tes) n. [L., fr. Gr. fr. fire. See Pyre.] (Min.) A name given to a number of metallic minerals,
sulphides of iron, copper, cobalt, nickel, and tin, of a white or yellowish color.
The term was originally applied to the mineral pyrite, or iron pyrites, in allusion to its giving sparks when
struck with steel.
Arsenical pyrites,
arsenopyrite. — Auriferous pyrites. See under Auriferous. — Capillary pyrites,
millerite. — Common pyrites, isometric iron disulphide; pyrite. — Hair pyrites, millerite. — Iron
pyrites. See Pyrite. — Magnetic pyrites, pyrrhotite. — Tin pyrites, stannite. — White iron pyrites,
orthorhombic iron disulphide; marcasite. This includes cockscomb pyrites spear pyrites, etc. — Yellow,
or Copper, pyrites, the sulphide of copper and iron; chalcopyrite.
Pyritic
(Py*rit"ic Py*rit"ic*al) a. (Min.) Of or pertaining to pyrites; consisting of, or resembling, pyrites.
Pyritiferous
(Pyr`i*tif"er*ous) a. [Pyrites + -ferous.] (Min.) Containing or producing pyrites.
Pyritize
(Pyr"i*tize) v. t. [Cf. F. pyritiser.] To convert into pyrites.
Pyritohedral
(Pyr`i*to*he"dral) a. [See Pyritohedron.] (Crystallog.) Like pyrites in hemihedral form.
Pyritohedron
(Pyr`i*to*he"dron) n. [Pyrite + Gr. base.] (Crystallog.) The pentagonal dodecahedron, a
common form of pyrite.
Pyritoid
(Pyr"i*toid) n. [Pyrite + - oid.] (Crystallog.) Pyritohedron. [R.]
Pyritology
(Pyr`i*tol"o*gy) n. [Gr. of fire + -logy.] The science of blowpipe analysis.
Pyritous
(Pyr"i*tous) a. Pyritic.
Pyro-
(Pyro-, Pyr-). Combining forms designating fire or heat; specifically (Chem.), used to imply an
actual or theoretical derivative by the action of heat; as in pyrophosphoric, pyrosulphuric, pyrotartaric,
pyrotungstic, etc.