What is the meaning of impulse?

noun

• An instinctive motive.
  • usage: "profound religious impulses"
  • synonyms: urge
• A sudden desire.
  • usage: "he bought it on an impulse"
  • synonyms: caprice, whim
• The electrical discharge that travels along a nerve fiber.
  • usage: "they demonstrated the transmission of impulses from the cortex to the hypothalamus"
  • synonyms: nerve impulse, nervous impulse, neural impulse
• Electronics) a sharp transient wave in the normal electrical state (or a series of such transients. ()
  • usage: "the pulsations seemed to be coming from a star"
  • synonyms: pulsation, pulsing, pulse
• The act of applying force suddenly.
  • usage: "the impulse knocked him over"
  • synonyms: impulsion, impetus
• An impelling force or strength.
  • usage: "the car's momentum carried it off the road"
  • synonyms: momentum