impulse

Etymology

Borrowed from Middle French impulser, from Latin impulsus.

For spelling, as in pulse, the -e (on -lse) is so the end is pronounced /ls/, rather than /lz/ as in pulls, and does not change the vowel (‘u’). Compare else, false, convulse.

Pronunciation

• IPA^(key): /ˈɪmpʌls/

• Audio (US):

  (file)

• Hyphenation: im‧pulse

Noun

impulse (plural impulses)

1. A thrust; a push; a sudden force that impels.
   • c. 1715-1716, Samuel Clarke, letter to Gottfried Wilhelm Leibniz

     All spontaneous animal motion is performed by mechanical impulse.

2. A wish or urge, particularly a sudden one prompting action.

   The impulse to learn drove me to study night and day.

   When I saw the new book, I couldn't resist the impulse to browse through it.

   • 1685, John Dryden, transl., “Preface”, in Sylvæ: Or, The Second Part of Poetical Miscellanies, London: […] Jacob Tonson, […], →OCLC; reprinted Menston, Yorkshire, London: Scolar Press, 1973, →ISBN, page 16:

     Theſe were my natural Impulses for the undertaking: […]

   • 1907 January, Harold Bindloss, chapter 20, in The Dust of Conflict, 1st Canadian edition, Toronto, Ont.: McLeod & Allen, →OCLC:

     Tony's face expressed relief, and Nettie sat silent for a moment until the vicar said “It was a generous impulse, but it may have been a momentary one, […] .”

   • 1930, Norman Lindsay, Redheap, Sydney, N.S.W.: Ure Smith, published 1965, →OCLC, page 218:

     An impulse urged him to plant a sudden blow on it, by he forced himself to consider the impolicy of such an act.

3. (physics) The integral of force over time.

   The total impulse from the impact will depend on the kinetic energy of the projectile.

Verb

impulse (third-person singular simple present impulses, present participle impulsing, simple past and past participle impulsed)

1. (transitive) To impel; to incite.
   • 1614, Walter Ralegh [i.e., Walter Raleigh], The Historie of the World […], London: […] William Stansby for Walter Burre, […], →OCLC, (please specify |book=1 to 5):

     With that force so impulsed and prest they are carried under the deepe Ocean.

References

• William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “impulse”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.
• “impulse”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.
• Douglas Harper (2001–2025) “impulse”, in Online Etymology Dictionary.

Pronunciation

• Homophones: impulsent, impulses

Verb

impulse

1. inflection of impulser:
   1. first/third-person singular present indicative/subjunctive
   2. second-person singular imperative

Verb

impulse

1. third-person singular past historic of impellere

Participle

impulse

1. vocative masculine singular of impulsus

Pronunciation

• IPA^(key): /imˈpulse/ [ĩmˈpul.se]
• Rhymes: -ulse
• Syllabification: im‧pul‧se

Verb

impulse

1. inflection of impulsar:
   1. first/third-person singular present subjunctive
   2. third-person singular imperative