impulse

Etymology

It is borrowed from Latin impulsus (“a push against, pressure, shock; incitement”),^[2][3][4][5] a noun from the participial stem of impellō (“to strike against, push against”),^[2][3][6] the source of impel.^[2] The Latin verb is formed from in- (“into, on, upon”) and pellō (“to push, drive”),^[2][7] which Watkins traces to Proto-Indo-European *pel- (“to thrust, strike, drive”).^[2] Barnhart thinks the noun was probably a back-formation from impulsive, modelled on the Latin word.^[8] The verb is either from the noun or from impuls- (“driven on”), the participial stem;^[3][9][6] the OED compares the obsolete verb French impulser.^[3] Hoad relates the word to pulse.^[10]

Earliest recorded meaning

The verb, to give an impulse to, impel or instigate, is recorded first, in Florio's Italian dictionary of 1611.^[3][11][9] The noun is dated 1647 by Barnhart and Merriam-Webster, for a sudden driving force,^[8][11] and 1650 by the OED, in Ashmole's translation of d'Espagnet, for an act of impelling, a thrust or push.^[3] Etymonline dates the noun to the early 15th century,^[2] but the Middle English word of that time is impulsioun, driving or thrusting, used about 1425 in a surgical text.^[12]

Semantic evolution

From 1660 the physical sense was applied to the mind, for a force or influence exerted on it from outside, an incitement or instigation.^[3][6] In 1702, in Clarendon, it is recorded for a stimulus to action arising from some state of mind or feeling, a sense that Etymonline finds by the 1640s.^[3][2] The modern everyday sense, a sudden inclination to act without thinking, is recorded from 1763, in Burke.^[3] Johnson (1755) gave "communicated force", "influence acting upon the mind; motive" and "hostile impression".^[13] Science gave the word new technical uses: in dynamics, a very large force acting for a very short time (1796), and later the product of a force and the time for which it acts (1859);^[3][6] in medicine, the beat of the heart felt on the chest wall (1873);^[3] in physiology, the wave of excitation that passes along a nerve, in the mid 19th century;^[6] and in electricity, a sudden brief change in voltage or current (1883), more often called a pulse.^[3] The attributive use for purchases made on a whim dates from 1955, in impulse buyer.^[2]

Timeline

• 1611 – verb, to impel, instigate (Florio).^[3]
• 1647 – noun, a sudden driving force.^[8][11]
• 1650 – an act of impelling; a thrust, push.^[3]
• 1660 – an influence on the mind from outside; incitement.^[3]
• 1702 – a stimulus to action arising from a state of mind.^[3]
• 1715 – momentum, impetus.^[3]
• 1763 – a sudden inclination to act without reflection (Burke).^[3]
• 1796 – dynamics, a very large force acting for a very short time.^[3]
• 1859 – the product of a force and the time it acts.^[3]
• 1873 – medicine, the impulse of the heart against the chest wall.^[3]
• 1883 – electricity, a sudden momentary change in voltage or current.^[3]
• 1955 – impulse buyer.^[2]

Modern meaning

Noun

1. A sudden urge or inclination to do something without thinking it over: On an impulse he booked a flight to Lisbon.
2. An instinctive drive, or a motive arising from a state of mind.
3. A force that sets something in motion; a thrust or push; impetus.
4. (physics) The product of a force and the time for which it acts, equal to the change in momentum it produces.
5. (physiology) A nerve impulse, the wave of electrical excitation that travels along a nerve.
6. (electronics) A sudden brief change in voltage or current; a pulse.
7. A tendency or trend.
8. (attributive) Bought or done on a whim: impulse buying.

Verb

1. (rare) To give an impulse to; to impel or instigate.

Word family

• specific impulse
• nerve impulse

Related words

• impel
• impulsion
• impulsive
• pulse

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c d e f g h i j k l m n o p q r s t u v Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
4. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
5. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
6. ^ a b c d e Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
8. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
9. ^ a b Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
10. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
11. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
12. ^ Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
13. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.