ordeal (n.)youdaoicibaDictYouDict[ordeal 词源字典]
Old English ordel, ordal, "trial by physical test," literally "judgment, verdict," from Proto-Germanic noun *uz-dailjam (cognates: Old Saxon urdeli, Old Frisian urdel, Dutch oordeel, German urteil "judgment"), literally "that which is dealt out" (by the gods), from *uzdailijan "share out," related to Old English adælan "to deal out" (see deal (n.1)). Curiously absent in Middle English, and perhaps reborrowed 16c. from Medieval Latin or Middle French, which got it from Germanic.

The notion is of the kind of arduous physical test (such as walking blindfolded and barefoot between red-hot plowshares) that was believed to determine a person's guilt or innocence by immediate judgment of the deity, an ancient Teutonic mode of trial. English retains a more exact sense of the word; its cognates in German, etc., have been generalized.

Metaphoric extension to "anything which tests character or endurance" is attested from 1650s. The prefix or- survives in English only in this word, but was common in Old English and other Germanic languages (Gothic ur-, Old Norse or-, etc.) and originally was an adverb and preposition meaning "out."[ordeal etymology, ordeal origin, 英语词源]
order (n.)youdaoicibaDictYouDict
early 13c., "body of persons living under a religious discipline," from Old French ordre "position, estate; rule, regulation; religious order" (11c.), from earlier ordene, from Latin ordinem (nominative ordo) "row, rank, series, arrangement," originally "a row of threads in a loom," from Italic root *ord- "to arrange, arrangement" (source of ordiri "to begin to weave;" compare primordial), of unknown origin.

Meaning "a rank in the (secular) community" is first recorded c. 1300; meaning "command, directive" is first recorded 1540s, from the notion of "to keep in order." Military and honorary orders grew our of the fraternities of Crusader knights. Business and commerce sense is attested from 1837. In natural history, as a classification of living things, it is first recorded 1760. Meaning "condition of a community which is under the rule of law" is from late 15c.

Phrase in order to (1650s) preserves etymological notion of "sequence." The word reflects a medieval notion: "a system of parts subject to certain uniform, established ranks or proportions," and was used of everything from architecture to angels. Old English expressed many of the same ideas with endebyrdnes. In short order "without delay" is from 1834, American English; order of battle is from 1769.
order (v.)youdaoicibaDictYouDict
c. 1200, "give order to, to arrange in order," from order (n.). Meaning "to give orders for or to" is from 1540s. Related: Ordered; ordering.
orderly (adv.)youdaoicibaDictYouDict
late 15c., "in due order," from order + -ly (2).
orderly (adj.)youdaoicibaDictYouDict
"arranged in order," 1570s, from order (n.) + -ly (1).
orderly (n.)youdaoicibaDictYouDict
"military attendant who carries orders," 1781, short for orderly corporal, etc. Extended 1809 to an attendant at a hospital (originally a military hospital) charged with keeping things in order and clean. See orderly (adj.).
ordinal (n.)youdaoicibaDictYouDict
early 14c., "book setting forth the order of services in the Church," from Late Latin adjective ordinalis (see ordinal (adj.)).
ordinal (adj.)youdaoicibaDictYouDict
late 14c., "regular, ordinary," from Old French ordinel and directly from Late Latin ordinalis ""showing order, denoting an order of succession," from Latin ordo (genitive ordinis) "row, series" (see order (n.)). Meaning "marking position in an order or series" is from 1590s.
ordinance (n.)youdaoicibaDictYouDict
c. 1300, "an authoritative direction, decree, or command" (narrower or more transitory than a law), from Old French ordenance (Modern French ordonnance) or directly from Medieval Latin ordinantia, from Latin ordinantem (nominative ordinans), present participle of ordinare "put in order" (see ordain). By early 14c. senses had emerged of "arrangement in ranks or rows" (especially in order of battle), also "warlike provisions, equipment" (a sense now in ordnance).
ordinary (adj.)youdaoicibaDictYouDict
early 15c., "belonging to the usual order or course," from Old French ordinarie "ordinary, usual" and directly from Latin ordinarius "customary, regular, usual, orderly," from ordo (genitive ordinis) "order" (see order (n.)). Its various noun usages, dating to late 14c. and common until 19c., now largely extinct except in out of the ordinary (1893). In British education, Ordinary level (abbrev. O level), "lowest of the three levels of General Certificate of Education," is attested from 1947. Related: Ordinarily.
ordinate (adj.)youdaoicibaDictYouDict
late 14c., from Latin ordinatus, past participle of ordinare "arrange, set in order" (see ordain). Related: Ordinately.
ordinate (v.)youdaoicibaDictYouDict
1560s, from Latin ordinatus, past participle of ordinare "arrange, set in order" (see ordain). Related: Ordinated; ordinating.
ordination (n.)youdaoicibaDictYouDict
early 15c., "the act of conferring holy orders," from Old French ordinacion (12c.) or directly from Latin ordinationem (nominative ordinatio) "a setting in order, ordinance," noun of action from past participle stem of ordinare "arrange" (see ordain).
ordnance (n.)youdaoicibaDictYouDict
"cannon, artillery," 1540s, a clipped form of ordinance (q.v.) which was attested from late 14c. in the sense of "military materials, provisions of war;" a sense now obsolete but which led to those of "engines for discharging missiles" (early 15c.) and "branch of the military concerned with stores and materials" (late 15c.). The shorter word was established in these distinct senses by 17c. Ordnance survey (1833), official survey of Great Britain and Ireland, was undertaken by the government under the direction of the Master-General of the Ordnance (the natural choice, gunners being thoroughly trained in surveying ranges and distances).
Ordovician (adj.)youdaoicibaDictYouDict
geological period following the Cambrian and preceding the Silurian, 1879, coined by English geologist Charles Lapworth (1842-1920) from Latin Ordovices, name of an ancient British tribe in North Wales. The period so called because rocks from it first were studied extensively in the region around Bala in North Wales. The tribe's name is Celtic, literally "those who fight with hammers," from Celtic base *ordo "hammer" + PIE *wik- "to fight, conquer" (see victor).
ordure (n.)youdaoicibaDictYouDict
late 14c., from Old French ordure "filth, uncleanliness" (12c.), from ord, ort "filthy, dirty, foul," from Latin horridus "dreadful" (see horrid).
ore (n.)youdaoicibaDictYouDict
12c., a merger of Old English ora "ore, unworked metal" (related to eorþe "earth," see earth; and cognate with Low German ur "iron-containing ore," Dutch oer, Old Norse aurr "gravel"); and Old English ar "brass, copper, bronze," from Proto-Germanic *ajiz- (cognates: Old Norse eir "brass, copper," German ehern "brazen," Gothic aiz "bronze"), from PIE root *aus- (2) "gold" (see aureate). The two words were not fully assimilated till 17c.; what emerged has the form of ar but the meaning of ora.
ore rotundoyoudaoicibaDictYouDict
Latin, literally "with round mouth," from ablative of os "mouth" (see oral) + ablative of rotundus "round" (see rotund). From Horace ("Grais ingenium, Grais dedit ore rotundo Musa loqui," in "Ars Poetica").
oread (n.)youdaoicibaDictYouDict
1580s, from Latin Oreas (genitive Oreadis), from Greek Oreias "mountain nymph," from oros "mountain," perhaps from PIE root *ergh- "to mount" (see orchestra).
oregano (n.)youdaoicibaDictYouDict
1771, from Spanish or American Spanish oregano, from Latin origanus, origanum, from Greek oreiganon, from oros "mountain" (see oread) + ganos "brightness, ornament." The older form of the word in English was the Latin-derived origanum (mid-13c.), also origan (early 15c.). In Europe, the dried leaves of wild marjoram; in America, a different, and more pungent, shrub.