"of or pertaining to King Pyrrhus of Epirus," 1885, usually in the phrase Pyrrhic victory "success obtained at too great a cost," in reference to Pyrrhus's rout of Roman armies at Asculum, in Apulia, 279 B.C.E., which came at such cost to his own troops that he was unable to follow up and attack Rome itself, and is said to have remarked, "one more such victory and we are lost." The name is Greek and means "reddish" or "red-haired," from pyrrhos "flame-colored," from pyr "fire" (from PIE root *paewr- "fire").
"dance in armor" (1590s), also a type of metrical foot of two short syllables (1620s), from Latin pyrrhicha, from Greek pyrrikhē orkhēsis, the war-dance of ancient Greece, in quick and light measure, accompanied by the flute, traditionally named for its inventor, Pyrrikhos. The name means "reddish, red-haired," from pyrrhos "flame-colored," from pyr "fire" (from PIE root *paewr- "fire"). As an adjective, "of or pertaining to the pyrrhic," from 1749.
1590s, "pertaining to Pyrrho" (Greek Pyrrhōn, c. 360-c. 275 B.C.E.), skeptic philosopher of Elis, who held the impossibility of attaining certainty of knowledge. The name means "reddish" or "red-haired," from pyrrhos "flame-colored," from pyr "fire" (from PIE root *paewr- "fire"). Related: Pyrrhonism; Pyrrhonist.
The doctrine of Pyrrho was that there is just as much to be said for as against any opinion whatever ; that neither the senses nor the reason are to be trusted in the least ; and that when we are once convinced we can know nothing, we cease to care, and in this way alone can attain happiness. It is said that Pyrrho would take no ordinary practical precautions, such as getting out of the way of vehicles. [Century Dictionary]
1540s, from Latin Pythagoreus "of or pertaining to Pythagoras" of Samos, Greek philosopher (6c. B.C.E.) said to have travelled to Egypt and Babylon, whose teachings included transmigration of the soul and vegetarianism (these are some of the commonest early allusions in English).
Also in reference to a school he supposedly founded in Crotona in Italy. As a noun, "a follower of Pythagoras," by 1540s. The Pythagorean theorem is the 47th of the first book of Euclid: The area of the square whose side is the hypotenuse of a right triangle is equal to the sum of the areas of the squares on the other two sides.
"priestess of Apollo at Delphi," who received his oracles in the inner sanctuary of the great temple, 1842, from Greek pythia (hiereia) "(Priestess) of Pythian Apollo," from a variant form of Pythios, an epithet of Apollo, from Pytho, older name of the region of Delphi (see python).
1580s, name of a fabled serpent, slain by Apollo near Delphi, from Latin Python, from Greek Pythōn "serpent slain by Apollo," probably related to Pythō, the old name of Delphi. Chaucer has it (late 14c.) as Phitoun.
This might be related to pythein "to rot," or from PIE *dhubh-(o)n-, from *dheub- "hollow, deep, bottom, depths," and used in reference to the monsters who inhabit them. Loosely used for "any very large snake," hence the zoological application to large non-venomous snakes of the tropics (1836, originally in French). Related: Pythonic.
1975, in reference to the style of humor popularized by the comedy troupe in the British TV series "Monty Python's Flying Circus."
late 14c., phitonesse, Phitonissa, "woman with the power of soothsaying," from Old French phitonise (13c.) and Medieval Latin phitonissa, from Late Latin pythonissa, used in Vulgate of the Witch of Endor (I Samuel xxviii.7), and often treated as her proper name. It is the fem. of pytho "familiar spirit;" which ultimately is connected with the title of the prophetess of the Delphic Oracle, Greek pythia hiereia, from Pythios, an epithet of Apollo, from Pythō, an older name of the region of Delphi (see python). The classical spelling was restored 16c.