Pyrgoidal, pir-goi′dal, adj. tower-shaped. [Gr., pyrgos, a tower.]
Pyrheliometer, pir-hē-li-om′e-tėr, n. an instrument for measuring the intensity of the sun.—adj. Pyrheliomet′ric. [Gr. pyr, fire, hēlios, sun, metron, measure.]
Pyriform, pir′i-form, adj. pear-shaped. [L. pirum, a pear, forma, form.]
Pyrite, pī′rīt, n. native iron disulphide of a pale-yellow colour and very hard—also Iron pyrites.—Copper pyrites, yellow sulphide of copper and iron. [L.,—Gr. pyrites, a flint—pyr, fire.]
Pyritegium, pir-i-tē′ji-um, n. the curfew-bell. [Low L.]
Pyrites, pir-ī′tēz, n. a term applied to a large class of mineral compounds of metals with sulphur, or with arsenic, or with both—crystalline, hard, generally brittle, and frequently yellow.—adjs. Pyritā′ceous; Pyrit′ic, -al; Pyritif′erous.—v.t. Pyr′itise, to convert into pyrites.—n. Pyritol′ogy, knowledge of pyrites.—adj. Pyr′itous. [L.,—Gr. pyr, fire.]
Pyritohedron, pī-rī-tō-hē′dron, n. a pentagonal dodecahedron.—adj. Pyritohē′dral. [Gr. pyritēs, pyrites, hedra, a seat.]
Pyro-acetic, pī′rō-a-set′ik, adj. relating to acetic acid under heat.
Pyroballogy, pī-rō-bal′ō-ji, n. the art of throwing fire: (Sterne) the science of artillery. [Gr. pyr, fire, ballein, to throw, logia—legein, to speak.]
Pyroclastic, pī-rō-klas′tik, adj. formed by volcanic agencies. [Gr. pyr, fire, klastos, broken.]