pr. n. [ L., fr. Gr. Plou`twn. ] 1. (Class. Myth.) The son of Saturn and Rhea, brother of Jupiter and Neptune; the dark and gloomy god of the Lower World. [ 1913 Webster ]

2. The ninth planet of the Solar System, the smallest (5700 km radius) and most distant from the sun. The suggestion has been made that it more closely resembles a large close comet than a planet. Its orbit has an eccentricity of 0.248, larger than that of any other planet; it varies from 4.44 to 7.37 billion km distance from the sun. [ PJC ]

Pluto is an oddball among its eight sister planets. It's the smallest in both size and mass, and has the most elliptical orbit. It moves in a plane tilted markedly away from the other planets' orbits. Moreover, Pluto is the only planet made almost entirely of ice. Ron Cohen (Science News, Feb. 27, 1999, p. 139)

Pluto monkey (Zool.), a long-tailed African monkey (Cercopithecus pluto), having side whiskers. The general color is black, more or less grizzled; the frontal band is white. [ 1913 Webster ]

n. [ Gr. ploutokrati`a; plou^tos wealth + kratei^n to be strong, to rule, fr. krato`s strength: cf. F. plutocratie. ] A form of government in which the supreme power is lodged in the hands of the wealthy classes; government by the rich; also, a controlling or influential class of rich men. [ 1913 Webster ]

n. One whose wealth gives him power or influence; one of the plutocracy. [ 1913 Webster ]

a. Of or pertaining to plutocracy; as, plutocratic ideas. Bagehot. [ 1913 Webster ]

n. [ Gr. &unr_; wealth + -logy. ] The science which treats of wealth. [ 1913 Webster ]

a. [ L. Plutonius, Gr. &unr_;: cf. F. plutonien. ] Plutonic. Poe. [ 1913 Webster ]

n. (Geol.) A Plutonist. [ 1913 Webster ]

a. [ Cf. F. plutonique. See Pluto. ] 1. Of or pertaining to Pluto; Plutonian; hence, pertaining to the interior of the earth; subterranean. [ 1913 Webster ]

2. Of, pertaining to, or designating, the system of the Plutonists; igneous; as, the Plutonic theory. [ 1913 Webster ]

Plutonic action (Geol.), the influence of volcanic heat and other subterranean forces under pressure. --
Plutonic rocks (Geol.), granite, porphyry, and some other igneous rocks, supposed to have consolidated from a melted state at a great depth from the surface. Cf. Intrusive rocks, under Intrusive. --
Plutonic theory. (Geol.) See Plutonism. [ 1913 Webster ]

n. [ Cf. F. plutonisme. ] The theory, early advanced in geology, that the successive rocks of the earth's crust were formed by igneous fusion; -- opposed to the Neptunian theory. [ 1913 Webster ]

n. [ Cf. F. plutoniste. ] One who adopts the geological theory of igneous fusion; a Plutonian. See Plutonism. [ 1913 Webster ]