n pulsating movement of the heart or the sound it makes 心搏; 心跳声
*Your heartbeat is quite normal. 你的心跳得很正常.

n [U and C]
the action or sound of your heart as it pumps blood through your body
be a heartbeat away from sth
to be very close to a situation or position
in a heartbeat
AmE very quickly, without delay
　Things can change in a heartbeat.
the heartbeat of sth
AmE the main origin of activity or excitement in a place or organization