orator (n.)youdaoicibaDictYouDict[orator 词源字典]
late 14c., "one who pleads or argues for a cause," from Anglo-French oratour (Modern French orateur), from Latin orator "speaker," from orare "to speak, speak before a court or assembly, pray, plead," from PIE root *or- "to pronounce a ritual formula" (cognates: Sanskrit aryanti "they praise," Homeric Greek are, Attic ara "prayer," Hittite ariya- "to ask the oracle," aruwai- "to revere, worship"). Meaning "public speaker" is attested from early 15c.[orator etymology, orator origin, 英语词源]
oratorical (adj.)youdaoicibaDictYouDict
1580s, from orator or oratory + -ical, or else from Latin oratorius (see oratory (n.1)). Related: Oratorical; oratorically.
oratorio (n.)youdaoicibaDictYouDict
"long musical composition, usually with a text based on Scripture," 1727 (in English from 1640s in native form oratory), from Italian oratorio (late 16c.), from Church Latin oratorium (see oratory (n.2)), in reference to musical services in the church of the Oratory of St. Philip Neri in Rome, where old mystery plays were adapted to religious services.
oratory (n.1)youdaoicibaDictYouDict
"formal public speaking, the art of eloquence," 1580s, from Latin (ars) oratoria "oratorical (art)," fem. of oratorius "of speaking or pleading, pertaining to an orator," from orare "to speak, pray, plead" (see orator).
oratory (n.2)youdaoicibaDictYouDict
"small chapel," c. 1300, from Old French oratorie and directly from Late Latin oratorium "place of prayer" (especially the Oratory of St. Philip Neri in Rome, where musical services were presented), noun use of an adjective, as in oratorium templum, from neuter of Latin oratorius "of or for praying," from orare "to pray, plead, speak" (see orator).
orb (n.)youdaoicibaDictYouDict
mid-15c., "sphere, globe, something spherical or circular," from Old French orbe "orb, globe" (13c.) and directly from Latin orbem (nominative orbis) "circle, disk, ring, hoop, orbit," probably related to orbita "wheel track, rut," of unknown origin. Watkins suggests a connection with the root of orchid.

A three-dimensional extension of a word originally describing two-dimensional shapes. Astronomical sense is in reference to the hollow spheres that carried the planets and stars in the Ptolemaic system. As a verb from c. 1600. Orb weaver spider is first recorded 1889.
orbicular (adj.)youdaoicibaDictYouDict
"round, circular, spherical," mid-15c., from Old French orbiculaire "round, circular," or directly from Late Latin orbicularis "circular, orbicular," from Latin orbiculus, diminutive of orbis "circle" (see orb). Related: Orbicularity.
orbit (n.)youdaoicibaDictYouDict
late 14c., "the eye socket," from Old French orbite or directly from Medieval Latin orbita, transferred use of Latin orbita "wheel track, beaten path, rut, course, orbit" (see orb). Astronomical sense first recorded 1690s in English; it was in classical Latin, revived in Gerard of Cremona's translation of Avicenna. The Old English word for "eye socket" was eaghring.
orbit (v.)youdaoicibaDictYouDict
1946, from orbit (n.). Related: Orbited; orbiting.
orbital (adj.)youdaoicibaDictYouDict
1540s, with reference to eye sockets; 1839 with reference to heavenly bodies; from orbit (n.) + -al (1).
orbiter 1954youdaoicibaDictYouDict
agent noun from orbit (v.).
orc (n.)youdaoicibaDictYouDict
"ogre, devouring monster," Old English orcþyrs, orcneas (plural), perhaps from a Romanic source akin to ogre, and ultimately from Latin Orcus "Hell," a word of unknown origin. Revived by J.R.R. Tolkien (1892-1973) as the name of a brutal race in Middle Earth.
But Orcs and Trolls spoke as they would, without love of words or things; and their language was actually more degraded and filthy than I have shown it. ["Return of the King," 1955]
orca (n.)youdaoicibaDictYouDict
"killer whale," introduced as a generic term for the species by 1841, from earlier use in scientific names, from Latin orca "cetacean, a kind of whale." Earlier in English, orc, ork "large whale" (c. 1590), from French orque, had been used vaguely of sea monsters (see orc).
orchard (n.)youdaoicibaDictYouDict
late Old English orceard "fruit garden," earlier ortgeard, perhaps reduced from wortgeard, from wort (Old English wyrt "vegetable, plant root") + geard "garden, yard" (the word also meant "vegetable garden" until 15c.); see yard (n.1). First element influenced in Middle English by Latin hortus (in Late Latin ortus) "garden," which also is from the root of yard (n.1).
orchestra (n.)youdaoicibaDictYouDict
c. 1600, "area in an ancient theater for the chorus," from Latin orchestra, from Greek orkhestra, semicircular space where the chorus of dancers performed, with suffix -tra denoting place + orkheisthai "to dance," intensive of erkhesthai "to go, come," from PIE root *ergh- "to mount" (cognates: Sanskrit rghayati "trembles, rages, raves," rnoti "rises, moves," arnah "welling stream;" Old Persian rasatiy "he comes;" Greek ornynai "to rouse, start;" Latin oriri "to rise," origo "a beginning;" Gothic rinnan, Old English irnan "to flow, run"). In ancient Rome, it referred to the place in the theater reserved for senators and other dignitaries. Meaning "group of musicians performing at a concert, opera, etc." first recorded 1720; "part of theater in front of the stage" is from 1768.
orchestral (adj.)youdaoicibaDictYouDict
1811, from orchestra + -al (1).
orchestrate (v.)youdaoicibaDictYouDict
"to compose or arrange (music) for an orchestra," 1855, back-formation from orchestration. The figurative sense is attested from 1883. Related: Orchestrated; orchestrating.
orchestration (n.)youdaoicibaDictYouDict
1840, from French orchestration or else a native noun of action from orchestrate.
orchid (n.)youdaoicibaDictYouDict
1845, introduced by John Lindley in "School Botanty," from Modern Latin Orchideæ (Linnaeus), the plant's family name, from Latin orchis, a kind of orchid, from Greek orkhis (genitive orkheos) "orchid," literally "testicle," from PIE *orghi-, the standard root for "testicle" (cognates: Avestan erezi "testicles," Armenian orjik, Middle Irish uirgge, Irish uirge "testicle," Lithuanian erzilas "stallion"). The plant so called because of the shape of its root. Earlier in English in Latin form, orchis (1560s), and in Middle English it was ballockwort (c. 1300; see ballocks). Marred by extraneous -d- in an attempt to extract the Latin stem.
ordain (v.)youdaoicibaDictYouDict
late 13c., "to appoint or admit to the ministry of the Church," from stem of Old French ordener "place in order, arrange, prepare; consecrate, designate" (Modern French ordonner) and directly from Latin ordinare "put in order, arrange, dispose, appoint," from ordo (genitive ordinis) "order" (see order (n.)). The notion is "to confer holy orders upon." Meaning "to decree, enact" is from c. 1300; sense of "to set (something) that will continue in a certain order" is from early 14c. Related: Ordained; ordaining.