the force of blood pushing out on your artery walls
the pressure of the blood within the arteries. A blood pressure cuff is used to measure this pressure which is produced primarily by the contraction of the heart muscle. Its measurement is recorded by two numbers - the first (systolic pressure) is measured after the heart contracts and is highest and the second (diastolic pressure) is measured before the heart contracts and is the lowest. High blood pressure is called "hypertension".