dedication (n.)youdaoicibaDictYouDict[dedication 词源字典]
late 14c., "action of dedicating," from Old French dedicacion (14c., Modern French dédication) "consecration of a church or chapel," or directly from Latin dedicationem, noun of action from dedicare (see dedicate). Meaning "the giving of oneself to some purpose" is c. 1600; as an inscription in a book, etc., from 1590s.[dedication etymology, dedication origin, 英语词源]
deduce (v.)youdaoicibaDictYouDict
early 15c., from Latin deducere "lead down, derive" (in Medieval Latin, "infer logically"), from de- "down" (see de-) + ducere "to lead" (see duke (n.)). Originally literal; sense of "draw a conclusion from something already known" is first recorded 1520s, from Medieval Latin. Related: Deduced; deducing.
deduct (v.)youdaoicibaDictYouDict
early 15c., from Latin deductus, past participle of deducere "lead down, bring away;" see deduce, with which it formerly was interchangeable. Technically, deduct refers to taking away portions or amounts; subtract to taking away numbers. Related: Deducted; deducting.
deductible (adj.)youdaoicibaDictYouDict
1610s, "that may be deduced," also "that may be deducted;" from Latin deducere (see deduce) + -ible. As a noun, "deductible thing," by 1927.
deduction (n.)youdaoicibaDictYouDict
early 15c., "action of deducting," from Middle French déduction or directly from Latin deductionem (nominative deductio), noun of action from past participle stem of deducere (see deduce). Meaning "that which is deducted" is from 1540s. As a term in logic, from Late Latin use of deductio as a loan-translation of Greek apagoge.
deductive (adj.)youdaoicibaDictYouDict
1640s, from Latin deductivus, from deduct-, past participle stem of deducere "to deduce" (see deduce). Related: Deductively.
deed (n.)youdaoicibaDictYouDict
Old English dæd "a doing, act, action, transaction, event," from Proto-Germanic *dædis (cognates: Old Saxon dad, Old Norse dað, Old Frisian dede, Middle Dutch daet, Dutch daad, Old High German tat, German Tat "deed," Gothic gadeþs "a putting, placing"), from PIE *dhetis (cognates: Lithuanian detis "load, burden," Greek thesis "a placing, setting"), from *dhe- "place, put" (see do). Sense of "written legal document" is early 14c. As a verb, 1806, American English Related: Deeded; deeding.
Deely-bobber (n.)youdaoicibaDictYouDict
"headband with springs carrying ornaments," 1982 trademark name held by Ace Novelty Company. Earlier it had been a patent name for a type of building blocks, manufactured 1969-1973.
deem (v.)youdaoicibaDictYouDict
Old English deman "to judge, condemn, think, compute," from root of dom (see doom (n.)). Originally "to pronounce judgment" as well as "to form an opinion." The two judges of the Isle of Man were called deemsters in 17c., a title formerly common throughout England and Scotland and preserved in the surname Dempster.
deemedyoudaoicibaDictYouDict
past tense of deem (q.v.).
deep (adj.)youdaoicibaDictYouDict
Old English deop "profound, awful, mysterious; serious, solemn; deepness, depth," deope (adv.), from Proto-Germanic *deupaz (cognates: Old Saxon diop, Old Frisian diap, Dutch diep, Old High German tiof, German tief, Old Norse djupr, Danish dyb, Swedish djup, Gothic diups "deep"), from PIE *dheub- "deep, hollow" (cognates: Lithuanian dubus "deep, hollow, Old Church Slavonic duno "bottom, foundation," Welsh dwfn "deep," Old Irish domun "world," via sense development from "bottom" to "foundation" to "earth" to "world").

Figurative senses were in Old English; extended 16c. to color, sound. Deep pocket "wealth" is from 1951. To go off the deep end "lose control of oneself" is slang first recorded 1921, probably in reference to the deep end of a swimming pool, where a person on the surface can no longer touch bottom. When 3-D films seemed destined to be the next wave and the biggest thing to hit cinema since talkies, they were known as deepies (1953).
deep (n.)youdaoicibaDictYouDict
Old English deop "deep water," especially the sea, from the source of deep (adj.).
deep six (n.)youdaoicibaDictYouDict
"place where something is discarded," by 1921 (in phrase give (something) the deep six), originally in motorboating slang, perhaps from earlier underworld noun sense of "the grave" (1929), which is perhaps a reference to the usual grave depth of six feet. But the phrase (in common with mark twain) also figured in the sailing jargon of sounding, for a measure of six fathoms:
As the water deepened under her keel the boyish voice rang out from the chains: "By the mark five--and a quarter less six--by the deep six--and a half seven--by the deep eight--and a quarter eight." ["Learning the Road to Sea," in "Outing" magazine, Feb. 1918]
In general use by 1940s. As a verb from 1953.
deep-freeze (n.)youdaoicibaDictYouDict
registered trademark (U.S. Patent Office, 1941) of a type of refrigerator; used generically for "cold storage" since 1949.
deep-seated (adj.)youdaoicibaDictYouDict
1741, "having its seat far below the surface;" see seat (v.). Figurative use is from 1847.
deepen (v.)youdaoicibaDictYouDict
c. 1600, from deep (adj.) + -en (1). Related: Deepened; deepening. The earlier verb had been simply deep, from Old English diepan.
deeply (adv.)youdaoicibaDictYouDict
Old English deoplice (see deep (adj.)), used in both literal and figurative senses.
deer (n.)youdaoicibaDictYouDict
Old English deor "animal, beast," from Proto-Germanic *deuzam, the general Germanic word for "animal" (as opposed to man), but often restricted to "wild animal" (cognates: Old Frisian diar, Dutch dier, Old Norse dyr, Old High German tior, German Tier "animal," Gothic dius "wild animal," also see reindeer), from PIE *dheusom "creature that breathes," from root *dheu- (1) "cloud, breath" (cognates: Lithuanian dusti "gasp," dvesti "gasp, perish;" Old Church Slavonic dychati "breathe").

For prehistoric sense development, compare Latin animal from anima "breath"). Sense specialization to a specific animal began in Old English (usual Old English for what we now call a deer was heorot; see hart), common by 15c., now complete. Probably via hunting, deer being the favorite animal of the chase (compare Sanskrit mrga- "wild animal," used especially for "deer"). Deer-lick is first attested 1778, in an American context.
deerskin (n.)youdaoicibaDictYouDict
late 14c., from deer + skin (n.).
def (adj.)youdaoicibaDictYouDict
"excellent," first recorded 1979 in Black English, perhaps a shortened form of definite, or from a Jamaican variant of death.