"in the time of, in the course of, throughout the continuance of," late 14c., duryng (earlier durand, mid-14c.), present participle of the long-obsolete verb duren "to last, endure, continue, be or exist" (mid-13c.), which is from Old French durer, from Latin durare "to harden," from durus "hard" (from PIE root *deru- "be firm, solid, steadfast"). During the day is "while the day endures," and the prepositional usage is a transference into English of a Latin ablative absolute (compare durante bello "during (literally 'enduring') the war").

also *dreu-, Proto-Indo-European root meaning "be firm, solid, steadfast," with specialized senses "wood," "tree" and derivatives referring to objects made of wood.

It forms all or part of: betroth; Dante; dendrite; dendro-; dendrochronology; dour; Druid; drupe; dryad; dura mater; durable; durance; duration; duress; during; durum; endure; hamadryad; indurate; obdurate; perdurable; philodendron; rhododendron; shelter; tar (n.1) "viscous liquid;" tray; tree; trig (adj.) "smart, trim;" trim; troth; trough; trow; truce; true; trust; truth; tryst.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit dru "tree, wood," daru "wood, log, timber;" Greek drys "oak," drymos "copse, thicket," doru "beam, shaft of a spear;" Old Church Slavonic drievo "tree, wood," Serbian drvo "tree," drva "wood," Russian drevo "tree, wood," Czech drva, Polish drwa "wood;" Lithuanian drūtas "firm," derva "pine, wood;" Welsh drud, Old Irish dron "strong," Welsh derw "true," Old Irish derb "sure," Old Irish daur, Welsh derwen "oak;" Albanian drusk "oak;" Old English treo, treow "tree," triewe "faithful, trustworthy, honest."

"restriction to limited allotments," 1865, verbal noun from ration (v.). Specifically of restrictions during wartime from 1917, in reference to conditions in England during the late stages of World War I.

"supporter or adherent of a sovereign" (especially in times of civil war), "a monarchist," 1640s, from royal + -ist. In England, a partisan of Charles I and II during the Civil War; in the U.S., an adherent of British government during the Revolution; in France, a supporter of the Bourbons.

"work done during the night," 1590s, from night + work (n.). Old English had nihtweorc.

c. 1300, "at night, at evening, through or during the night," from over- + night (n.). Originally especially "during the night just passed." The meaning "in the course of a single night, hence seemingly instantaneously" is attested from 1939. As a noun, "a stop lasting one night," by 1959. As a verb, "to pass the night," by 1891.

"confinement during and after childbirth," 1863, from Latin puerperus (see puerperal). From c. 1600 in navitized form puerpery.

1640s, "during, in the process of, for the time of the continuance of," a preposition formed on the model of French pendant "during," literally "hanging," present participle of pendere "to hang, cause to hang" (from PIE root *(s)pen- "to draw, stretch, spin").

The meaning is patterned on "not decided" as a secondary sense of Latin pendente (literally "hanging") in the legal phrase pendente lite "while the suit is pending, during the litigation" (with the ablative singular of lis "suit, quarrel"). The use of the present participle before nouns caused it to be regarded as a preposition. As an adjective from 1797.