- 1[countable, usually singular, uncountable] impulse (to do something) a sudden strong wish or need to do something, without stopping to think about the results He had a sudden impulse to stand up and sing. I resisted the impulse to laugh. Her first impulse was to run away. The door was open and on (an) impulse she went inside. He tends to act on impulse.
- 2[countable] (technology) a force or movement of energy that causes something else to react nerve/electrical impulses The impulse is conducted along the length of the wire.
- 3[countable, usually singular, uncountable] (formal) something that causes someone or something to do something or to develop and make progress to give an impulse to the struggling car industry He was motivated by the impulse for social reform.