1590s, "being," from Late Latin entitatem (nominative entitas), from ens (genitive entis) "a thing," proposed by Caesar as present participle of esse "be" (see is), to render Greek philosophical term to on "that which is" (from neuter of present participle of einai "to be," from PIE root *es- "to be"). Originally abstract; concrete sense in English is from 1620s.
early 14c., quantite, "amount, magnitude, the being so much in measure or extent," from Old French quantite, cantite (12c., Modern French quantité) and directly from Latin quantitatem (nominative quantitas) "relative greatness or extent," coined as a loan-translation of Greek posotes (from posos "how great? how much?") from Latin quantus "of what size? how much? how great? what amount?," correlative pronominal adjective (from PIE root *kwo-, stem of relative and interrogative pronouns).
From late 14c. as "that which has quantity, a concrete quantity;" from 1610s in the concrete sense of "an object regarded as more or less." In prosody and metrics, "the relative time occupied in uttering a vowel or syllable" (distinguishing it as long or short) by 1560s. Latin quantitatem also is the source of Italian quantita, Spanish cantidad, Danish and Swedish kvantitet, German quantitat.
1784, "descent of a Hindu deity to earth in an incarnate or tangible form," from Sanskrit avatarana "descent" (of a deity to the earth in incarnate form), from ava- "off, down" (from PIE root *au- (2) "off, away") + base of tarati "(he) crosses over," from PIE root *tere- (2) "cross over, pass through, overcome."
Meaning "concrete embodiment of something abstract" is from 1815. In computer use, it seems to trace to the novel "Snowcrash" (1992) by Neal Stephenson.
1757, "situated between two things;" 1818 as "serving as a mediator;" from French intermédiaire (17c.), from Latin intermedius "that which is between" (see intermediate). As a noun, "one who acts between others" from 1791 (Medieval Latin intermedium also was used as a noun). An earlier adjective was intermedial (1590s).
Intermediary, n., is, even with concrete sense of go-between or middleman or mediator, a word that should be viewed with suspicion & resorted to only when it is clear that every more ordinary word comes short of the need. [Fowler]
also nit-picker, "pedantic critic," by 1951, perhaps 1946, a figurative use, said to be originally military jargon; see nit (n.) + pick (v.).
Two long-time Pentagon stand-bys are fly-speckers and nit-pickers. The first of these nouns refers to people whose sole occupation seems to be studying papers in the hope of finding flaws in the writing, rather than making any effort to improve the thought or meaning; nit-pickers are those who quarrel with trivialities of expression and meaning, but who usually end up without making concrete or justified suggestions for improvement. [Collier's, Nov. 24, 1951]
late 14c., nocioun, "a general concept, conception," from Latin notionem (nominative notio) "concept, conception, idea, notice," noun of action from past participle stem of noscere "come to know," from PIE root *gno- "to know." Coined by Cicero as a loan-translation of Greek ennoia "act of thinking, notion, conception," or prolepsis "previous notion, previous conception."
Meaning "an opinion, a view, a somewhat vague belief" is from c. 1600; that of "a not very rational inclination, a whim" is by 1746. Notions in the concrete sense of "miscellaneous small articles of convenience or utensils" (such as sold by Yankee peddlers) is by 1803, American English, via the idea of "clever product of invention."
