Final answer:
The pulse site located over the heart on the left side under the nipple is known as the apical pulse.
Step-by-step explanation:
The pulse site located over the heart, specifically on the left side under the nipple, is the apical pulse. This pulse can be felt by placing the hand over the heart area, which, contrary to popular belief, is located closer to the center of the chest rather than the left side. Other common pulse sites include the radial artery in the wrist and the carotid artery in the neck. The apical pulse is typically auscultated (listened to with a stethoscope) rather than palpated (felt with fingers).