| pyrimidine |
an organic compound that is the fundamental form of certain bases that are constituents of nucleic acids. [2 definitions] |
| pyrite |
a common yellowish metallic mineral used as a source of iron and in the production of sulfuric acid; fool's gold. |
| pyrites |
any of a wide variety of minerals, such as pyrite, containing a metal and sulfur. |
| pyro- |
fire; heat. |
| pyroclastic |
relating to or consisting of fragments of rock that were formed by volcanic or igneous activity. |
| pyroelectricity |
an electrical charge produced in certain crystals as a result of temperature changes. |
| pyrography |
the art, practice, or process of burning designs on wood, leather, or the like with a heated tool or a flame. [2 definitions] |
| pyrolysis |
chemical decomposition or change induced by heat. |
| pyromania |
a psychological disorder characterized by the overpowering desire to start fires. |
| pyrometer |
an electrical instrument used to measure high temperatures. |
| pyrophoric |
of certain metals, capable of igniting spontaneously in air or within a nuclear reactor. |
| pyrosulfuric acid |
a corrosive acid used in the making of explosives and dyes. |
| pyrotechnic |
of or relating to fireworks. [3 definitions] |
| pyrotechnics |
(used with a sing. or pl. verb) the practice or art of making or using fireworks. [3 definitions] |
| pyroxylin |
a highly flammable nitrocellulose used in the manufacture of artificial silk, plastics, lacquer, and the like. |
| Pyrrhic victory |
a victory or achievement won at too great a cost. |
| pyrrole |
a colorless toxic compound that occurs in natural substances such as chlorophyll and various hydrocarbons. |
| Pythagoras |
a Greek philosopher and mathematician (582?-500? B.C.). |
| Pythagorean theorem |
in geometry, the theorem that in a right triangle the square of the hypotenuse is equal to the sum of the squares of the other two sides. |
| Pythian |
of or pertaining to ancient Delphi, the temple of Apollo there, or the oracle of that temple. [2 definitions] |
| python |
any of a number of nonpoisonous snakes of the Eastern Hemisphere that kill by crushing and suffocating their victims. [3 definitions] |