What is meant by 'systolic pressure' and 'diastolic pressure'? What are their normal values?

Systolic pressure: The pressure at which the blood leaves the heart through the aorta, during contraction phase.

Diastolic pressure: The minimum pressure in the arteries during the relaxation phase of the heart.

The normal value of systolic pressure is 120 mm Hg, while the normal diastolic pressure is 80 mm Hg.