impulse in WordNet English dictionary

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