noun (n)

• the rhythmic contraction and expansion of the arteries with each beat of the heart(noun.event)

  Synonym:
  beat, pulsation, pulse
  

  source: wordnet30
• a very short time (as the time it takes the eye to blink or the heart to beat)(noun.time)

  Synonym:
  blink of an eye, flash, instant, jiffy, new york minute, split second, trice, twinkling, wink
  

  source: wordnet30
• an animating or vital unifying force(noun.attribute)

  Example:
  New York is the commercial heartbeat of America.
  

  source: wordnet30