Online Etymology Dictionary

pandemonium (n.): 1667, Pandæmonium, in "Paradise Lost" the name of the palace built in the middle of Hell, "the high capital of Satan and all his peers," coined by John Milton (1608-1674) from Greek pan- "all" (see pan-) + Late Latin daemonium "evil spirit," from Greek daimonion "inferior divine power," from daimon "lesser god" (see demon).

Transferred sense "place of uproar" is from 1779; that of "wild, lawless confusion" is from 1865. Related: Pandemoniac; pandemoniacal; pandemonian; pandemonic.
pander (n.): "arranger of sexual liaisons, one who supplies another with the means of gratifying lust," 1520s, "procurer, pimp," from Middle English Pandare (late 14c.), used by Chaucer ("Troylus and Cryseyde"), who borrowed it from Boccaccio (who had it in Italian form Pandaro in "Filostrato") as name of the prince (Greek Pandaros), who procured the love of Cressida (his niece in Chaucer, his cousin in Boccaccio) for Troilus. The story and the name are medieval inventions. Spelling influenced by agent suffix -er.
pander (v.): "to indulge (another), to minister to base passions," c. 1600, from pander (n.). Related: Pandered; pandering.
pandiculation (n.): 1610s, noun of action from Latin pandiculat-, past participle stem of pandiculari "to stretch oneself," from pandere "to stretch" (see pace (n.)).
Pandora: 1570s, in Greek mythology, the first mortal woman, made by Hephaestus and given as a bride to Epimetheus, from Greek pandora "all-gifted" (or perhaps "giver of all"), from pan "all" (see pan-) + doron "gift," from PIE root *do- "to give" (see date (n.1)).

Pandora's box (1570s) refers to her gift from Zeus, which was foolishly opened by Epimetheus, upon which all the contents escaped. They were said to be the host of human ills (escaping to afflict mankind), or, in a later version, all the blessings of the god (escaping to be lost), except Hope, which alone remained.
pane (n.): mid-13c., "garment, part of a garment," later "side of a building, section of a wall," from Old French pan "section, piece, panel" (11c.), from Latin pannum (nominative pannus) "piece of cloth, garment," possibly from PIE root *pan- "fabric" (source also of Gothic fana "piece of cloth," Greek penos "web," Old English fanna "flag"). Sense of "window glass" first attested mid-15c.
panegyric (n.): "eulogy, laudation," c. 1600, from French panégyrique (1510s), from Latin panegyricus "public eulogy," originally an adjective, "for a public festival," from Greek panegyrikos (logos) "(a speech) given in a public assembly," from panegyris "public assembly (especially in honor of a god)," from pan- "all" (see pan-) + agyris "place of assembly," Aeolic form of agora (see agora).
panel (n.): early 14c., from Old French panel "piece of cloth, piece, saddle cushion" (Modern French panneau), from Vulgar Latin *pannellus, diminutive of Latin pannus "piece of cloth" (see pane). Anglo-French legalese sense of "piece of parchment (cloth) listing jurors" led by late 14c. to meaning "jury." General sense of "persons called on to advise, judge, discuss," etc. is from 1570s. Sense of "distinct part of surface of a wall, door, etc." is first recorded c. 1600.
panel (v.): mid-15c., "to empanel," from panel (n.). From 1630s as "to furnish (a room) with panels." Related: Paneled; paneling; panelling.
panelist (n.): 1950, American English, from panel (n.) + -ist. Originally in quiz shows.
panelling (n.): also paneling, 1800, verbal noun from panel (v.).
panem et circenses: Latin, literally "bread and circuses," supposedly coined by Juvenal and describing the cynical formula of the Roman emperors for keeping the masses content with ample food and entertainment.
Duas tantum res anxius optat, Panem et circenses [Juvenal, Sat. x.80].
panfish (n.): 1833, American English, from pan (n.1) + fish (n.).
pang (n.): 1520s, "sudden physical pain," of unknown origin, perhaps related to prong (prongys of deth is recorded from mid-15c.). Reference to mental or emotional pain is from 1560s. Related: Pangs.
Pangaea: "supercontinent of the late Paleozoic era," 1924, from Greek pan- "all" (see pan-) + gaia "earth" (see gaia). First attested in German, 1920, in Alfred Wegener's "Die Entstehung der Kontinente und Ozeane" (not found in 1914 first edition, according to OED).
Panglossian (adj.): "optimistic" (usually ironic or disparaging), 1831, from French Panglosse, name of the philosopher and tutor in Voltaire's "Candide" (1758), from pan- (see pan-) + Greek glossa, literally "tongue" (see gloss (n.2)).
pangolin (n.): 1774, "scaly toothless mammal of Java," from Malay peng-goling "roller," from its habit of curling into a ball; from peng- (denominative prefix) + goling "to roll." Later extended to related species in Asia and Africa.
panhandle (n.): "something resembling the handle of a pan," 1851, from pan (n.) + handle (n.). Especially in reference to geography, originally American English, from 1856, in reference to Virginia (now West Virginia; Florida, Texas, Idaho, Oklahoma, and Alaska also have them). Meaning "an act of begging" is attested from 1849, perhaps from notion of arm stuck out like a panhandle, or of one who handles a (beggar's) pan.
panhandle (v.): "to beg," 1888, from panhandle (n.) in the begging sense. Related: Panhandled; panhandling.
panhandler (n.): "one who begs," 1893, from panhandle (n.) in begging sense. Related: Panhandled; panhandler; panhandling.
Panhellenic (adj.): also Related: pan-Hellenic, 1847, "pertaining to or involving all the Greeks," from Greek Panhellenes "all the Hellenes;" see pan- + Hellenic. Related: Panhellenism.
panic (n.1): "mass terror," 1708, from earlier adjective (c. 1600, modifying fear, terror, etc.), from French panique (15c.), from Greek panikon, literally "pertaining to Pan," the god of woods and fields, who was the source of mysterious sounds that caused contagious, groundless fear in herds and crowds, or in people in lonely spots.

In the sense of "panic, fright" the Greek word is short for panikon deima "panic fright," from neuter of Panikos "of Pan." Meaning "widespread apprehension about financial matters" is first recorded 1757. Panic button in figurative sense is first recorded 1955, the literal sense apparently is from parachuting. Panic attack attested by 1970.
panic (n.2): type of grass, early 15c., from Old French panic "Italian millet," from Latin panicum "panic grass, kind of millet," from panus "ear of millet, a swelling" (compare panocha).
panic (v.): 1827, "to afflict with panic," from panic (n.). Intransitive sense of "to lose one's head, get into a panic" is from 1902. Related: Panicked; panicking.
panicky (adj.): 1869, from panic (n.1) + -y (2). Related: Panickiness.
panjandrum (n.): mock name for a pompous personage, 1755, invented by Samuel Foote (1720-1777) in a long passage full of nonsense written to test the memory of actor Charles Macklin (1697-1797), who said he could repeat anything after hearing it once.
panne (n.): 1794, from French panne "soft material, plush" (15c.), earlier penne (13c.), of unknown origin; perhaps from Latin penna "feather" (see pen (n.1)).
pannel: see panel.
pannier (n.): late 13c., "large basket for provisions," from Old French panier "basket," from Latin panarium "bread basket," from panis "bread," from PIE root *pa- "to feed" (see food).
pannikin (n.): "small metal cup," 1823, described as a Suffolk dialect word, from pan (n.) + diminutive suffix -kin.
Pannonia: ancient name of the region roughly corresponding to modern Hungary.
panocha (n.): also panoche, 1847, from American Spanish panocha "brown sugar," perhaps ultimately from Latin panucula "tuft," diminutive of panus "tuft, swelling; ear of millet" (see panic (n.2)).
panoply (n.): 1570s, from Greek panoplia "complete suit of armor," from pan- "all" (see pan-) + hopla (plural), "arms" of a hoplites ("heavily armed soldier"); see hoplite. Originally in English figurative, of "spiritual armor," etc. (a reference to Eph. vi); non-armorial sense of "any splendid array" first recorded 1829.
panoptic (adj.): 1826, from Greek panoptos "fully visible, seen by all," from panopes "all-seeing," from pan "all" (see pan-) + optos (see optic). Related: Panoptical.
panopticon (n.): 1768, a type of optical instrument or telescope, from Greek pan "all" (see pan-) + optikon, neuter of optikos "of or for sight" (see optic). Later the name of a type of prison designed by Bentham (1791) in which wardens had a constant view of all inmates, and "a showroom" (1850).
panorama (n.): 1796, "a painting on a revolving cylindrical surface," coined c. 1789 by inventor, Irish artist Robert Barker, literally "a complete view," from pan- "all" + Greek horama "sight, spectacle, that which is seen," from horan "to look, see," possibly from PIE root *wer- (4) "to perceive" (see ward (n.)). Meaning "comprehensive survey" is 1801.
panoramic (adj.): 1813; see panorama + -ic. Panoramic camera is attested from 1878.
pansexual (adj.): 1926 (pansexualism is from 1917), from pan- + sexual. Originally in reference to the view that the sex instinct plays the primary part in all human activity, mental and physical; this was held by his critics to be the view of Freud, therefore a term of reproach leveled at early psychology.
Panslavism (n.): 1846, from German Pansclavismus, coined as a linguistic term by Herkel in 1826.
pansy (n.): mid-15c., from Middle French pensée "a pansy," literally "thought, remembrance," from fem. past participle of penser "to think," from Latin pensare "consider," frequentative of pendere "to weigh" (see pendant). So called because it was regarded as a symbol of thought or remembrance. Meaning "effeminate homosexual man" is first recorded 1929.
pant (v.): mid-15c., perhaps a shortening of Old French pantaisier "gasp, puff, pant, be out of breath, be in distress" (12c.), probably from Vulgar Latin *pantasiare "be oppressed with a nightmare, struggle for breathing during a nightmare," literally "to have visions," from Greek phantasioun "have or form images, subject to hallucinations," from phantasia "appearance, image, fantasy" (see phantasm). Related: Panted; panting.
pant (n.): "a gasping breath," c. 1500, from pant (v.).
Pantaloon (n.): skinny, foolish old man in Italian comedy, 1580s; see pantaloons. As a kind of leggings, 1660s.
pantaloons (n.): 1660s, "kind of tights" (originally a French fashion and execrated as such by late 17c. English writers), associated with Pantaloun (1580s), silly old man character in Italian comedy who wore tight trousers over his skinny legs, from Italian Pantalone, originally San Pantaleone, Christian martyr, a popular saint in Venice (Pantaleone in the comedies represents the Venetian). The name is of Greek origin and means "all-compassionate" (or, according to Klein, "entirely lion"). Applied to tight long trousers (replacing knee-breeches) by 1798; pants is a shortened form first recorded 1840.
Panthalassa (n.): "universal sea," such as that which surrounded Pangaea, 1893 (Suess), from pan- "all" (see pan-) + Greek thalassa "sea" (see thalasso-).
pantheism (n.): "belief that God and the universe are identical," from pantheist (n.), which was coined (1705) by Irish deist John Toland (1670-1722), from Greek pan- "all" (see pan-) + theos "god" (see theo-).

Toland's word was borrowed into French, which from it formed panthéisme (1712) which returned to English as pantheism "the doctrine that all is god" in 1732 (no evidence that Toland used pantheism).

Greek pantheios meant "common to all gods" (see pantheon). Other words used at various times for similar notions include panentheism, "philosophy founded on the notion that all things are in God" (1874), from German (1828), coined by Karl Christian Friedrich Krause (1781-1832).
pantheist (n.): 1705, see pantheism + -ist.
pantheistic (adj.): 1732, from pantheist + -ic.
pantheon (n.): c. 1300, from Pantheon, name of a temple for all the gods built in Rome c. 25 B.C.E. by Agrippa (since 609 C.E. made into the Christian church of Santa Maria Rotonda), from Greek Pantheion (hieron) "(shrine) of all the gods," from pantheion, neuter of pantheios, from pan- "all" (see pan-) + theios "of or for the gods," from theos "god" (see theo-). Sense of any group of exalted persons is first found 1590s.
panther (n.): early 13c., from Old French pantere "panther" (12c.), from Latin panthera, from Greek panther "panther, leopard," probably of Oriental origin. Folk etymology derivation from Greek pan- "all" + ther "beast" led to many curious fables.