1856, "capable of being withdrawn," especially from one's taxes or income, with -ible + Latin deducere "lead down, derive" (in Medieval Latin, "infer logically"), from de "down" (see de-) + ducere "to lead" (from PIE root *deuk- "to lead"). As a noun, "amount of a loss which must be borne by the policy-holder in an insurance claim," by 1927. The older adjective is deducible (1610s).
early 15c., deduccioun, "a bringing, a leading;" mid-15c., "action of deducting; a taking away, a number or amount subtracted," from Old French deduction (Modern French déduction) and directly from Latin deductionem (nominative deductio) "a leading away, an escorting; a diminution," noun of action from past-participle stem of deducere "lead or bring away or down; derive" (in Medieval Latin, "infer logically"), from de "down" (see de-) + ducere "to lead," from PIE root *deuk- "to lead."
Meaning "that which is deducted" is from 1540s. As a term in logic, "derivation as a result from a known principle, an inference, conclusion," 1520s, from Late Latin use of deductio as a loan-translation of Greek apagoge. Related: Deductional.
1640s, "derivative" (a sense now obsolete); from 1660s in logic, "consisting of deduction; based on inference from accepted principles," from Latin deductivus"derivative," from deduct-, past-participle stem of deducere "to lead down, derive" (in Medieval Latin, "infer logically"), from de "down" (see de-) + ducere "to lead" (from PIE root *deuk- "to lead"). Related: Deductively.
"that which is done, acted, or performed, whether good or bad, great or small," Old English dæd "a doing, act, action; transaction, event," from Proto-Germanic *dethi- (source also of Old Saxon dad, Old Norse dað, Old Frisian dede, Middle Dutch daet, Dutch daad, Old High German tat, German Tat "deed, thing done," Gothic gadeþs "a putting, placing"), from PIE *dheti- "thing laid down or done; law; deed" (source also of Lithuanian dėtis "load, burden," Greek thesis "a placing, setting"), suffixed form of root *dhe- "to set, place, put" (compare do).
In law, "written document authenticated by seal of the person whose will it declares, especially for the purpose of conveying real estate" is from early 14c. As a verb, "convey or transfer by deed," 1806, American English. Related: Deeded; deeding.
"headband with two 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.
Old English deman "to judge, decide on consideration, condemn;, think, judge, hold as an opinion," from Proto-Germanic *domjanan(source also of Old Frisian dema"to judge," Old Saxon adomian, Middle Dutch doemen, Old Norse dma, Old High German tuomen, Gothic domjan "to deem, judge"), denominative of *domaz, from PIE root *dhe- "to set, put" (compare doom). Related: Deemed; deeming. Originally "to pronounce judgment" as well as "to form an opinion." Compare Old English, Middle English deemer "a judge." 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.
Old English deop "having considerable extension downward," especially as measured from the top or surface, also figuratively, "profound, awful, mysterious; serious, solemn," from Proto-Germanic *deupaz (source also of 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 root *dheub- "deep, hollow" (source also of 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").
By early 14c. "extensive in any direction analogous to downward," as measured from the front. From late 14c. of sound, "low in pitch, grave," also of color, "intense." By c. 1200, of persons, "sagacious, of penetrating mind." From 1560s, of debt., etc., "closely involved, far advanced."
Deep pocket as figurative of wealth is from 1951. To go off the deep end "lose control of oneself" is slang recorded by 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)., hard to understand
Old English deop "deep water," especially the sea, from the source of deep (adj.). Cognate with Old High German tiufi, German Tief, Teufe, Dutch diep, Danish dyb. General sense of "that which is of great depth" is by mid-14c.