pulsation
     n 1: (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" [syn: {pulsing},
           {pulse}, {impulse}]
     2: a periodically recurring phenomenon that alternately
        increases and decreases some quantity
     3: the rhythmic contraction and expansion of the arteries with
        each beat of the heart; "he could feel the beat of her
        heart" [syn: {pulse}, {heartbeat}, {beat}]
Source: WordNet® 2.0