Definition of "Impulse" :

noun: the act of applying force suddenly

"The impulse knocked him over."

noun: an impelling force or strength

noun: the electrical discharge that travels along a nerve fiber

"They demonstrated the transmission of impulses from the cortex to the hypothalamus."

noun: (electronics) a sharp transient wave in the normal electrical state (or a series of such transients)

noun: a sudden desire

"He bought it on an impulse."

noun: an instinctive motive

"Profound religious impulses."