from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Occurring or completed without perceptible delay: Relief was instantaneous.
- adj. Done or made as quickly or directly as possible: an instantaneous reply to my letter.
- adj. Present or occurring at a specific instant: instantaneous velocity; instantaneous pressure.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Occurring, arising, or functioning without any delay; happening within an imperceptibly brief period of time.
from the GNU version of the Collaborative International Dictionary of English
- adj. Done or occurring in an instant, or without any perceptible duration of time.
- adj. At or during a given instant
from The Century Dictionary and Cyclopedia
- Done or produced in an instant; occurring or acting without any perceptible lapse of time.
- In mech., existing in or referring to an instant of time; momentary: as, instantaneous position, displacement, velocity, acceleration, etc. (that is, the position, etc., at any instant).
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. occurring with no delay
From Medieval Latin īnstantāneus, from Latin īnstāns, īnstant-, present; see instant.(American Heritage® Dictionary of the English Language, Fourth Edition)
New Latin, 17th century (Wiktionary)