instant

Etymology 1

From Middle English instant (“infinitely short period of time”), from Old French instant (“assiduous, at hand”, adj), from Latin īnstāns, īnstantis (“present, pressing, urgent”, literally “standing near”), present active participle of īnstō (“to stand upon, be nearby”), from in- (“after”) + stō (“to stand”). Compare Old English instede (“immediately, on the spot, at once”). More at in, stand.

noun

1. A very short period of time; a moment.
   She paused for only an instant, which was just enough time for John to change the subject.
   On receiving the baton, steam was again turned on, and the train passed on to the bridge... when the train had got about 200 yards from the cabin [in the signal box], he observed sparks flying from the wheels; and after they had continued about three minutes, there was a sudden bright flash of light, and in an instant there was total darkness, the tail lamps of the train, the sparks, and flash of light, all, he said disappearing at the same instant. November 3 2021, Dr Joseph Brennan, “Boxes with functions across the centuries”, in RAIL, number 943, page 57, referring to the Tay Bridge disaster
2. A single, usually precise, point in time.
   The instant the alarm went off, he fled the building.
3. A beverage or food which has been pre-processed to reduce preparation time, especially instant coffee.
4. Ellipsis of instant camera.

Etymology 2

From French instant and Middle English instant, both from Old French, from Latin instans (“standing by, being near, present, also urgent, importunate”), present participle of instō (“to stand upon, press upon, urge, pursue, insist”), from in (“on, upon”) + stō (“to stand”); see state.

adj

1. (dated) Impending; imminent.
   Impending death is thine, and instant doom. 1703, Matthew Prior, an Ode to Colonel George Villiers
2. (dated) Urgent; pressing; acute.
3. (dated) Insistent; persistent.
   January 2, 1827, Thomas Carlyle, letter to Mrs. Carlyle, Scotsbrig I am beginning to be very instant for some sort of occupation.
4. (law) Present; current; extant.
   He received just two disciplinary reports prior to committing the instant offense, one in March 2019 for activating an alarm during a non-emergency situation, and one in May 2019 for failing to provide a urine specimen. December 28, 2019 Attorney Jeffery S. Levin, quoted in The Boston Globe, p. 3
5. Occurring immediately; immediate; present.
   No one, however, would have anything to do with him, as Mr. Keeson's orders in those respects were very strict ; he had often threatened any one of his employés with instant dismissal if he found him in company with one of these touts. 1905, Baroness Emmuska Orczy, chapter 2, in The Hocussing of Cigarette
6. Lasting for a short moment; momentary; short-lived.
7. Very quickly and easily prepared.
   instant coffee; instant noodles; instant mashed potato; instant photo
8. Of the current month.
   I refer to your letter of the 16th instant in regard to traffic disruption.

adv

1. (poetic) At once; immediately.
   He left the room for his relinquished sword, / And Julia instant to the closet flew. 1819, Lord Byron, Don Juan, I.182