1. A period of time so short as to be almost imperceptible. See Synonyms at moment.
2. A particular or precise time: at the instant of combustion.
3. Abbr. inst. The current month: your letter of the 15th instant.
4. A food or beverage designed for quick preparation.
1. Occurring at once; immediate: instant gratification.
2. Imperative; urgent: an instant need.
3. Now under consideration; present.
a. Commercially prepared or processed for quick and easy final preparation: an instant cake mix.
b. Appearing, done, or taking place with great quickness and ease: "She had the gift of instant intimacy" (Sylvia Jukes Morris).
c. Quickly and easily resolved or determined: instant lottery tickets.
At once; instantly.
[Middle English, from Old French, from Latin īnstāns, īnstant-, present, present participle of īnstāre, to approach : in-, on; see IN-2 + stāre, to stand; see stā- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.