The measurement "120/80 mmHg" refers to normal blood pressure levels in humans. The first number, 120, represents the systolic pressure, which is the force of blood against the artery walls when the heart beats. The second number, 80, indicates the diastolic pressure, which is the pressure in the arteries when the heart is at rest between beats. Blood pressure is measured in millimeters of mercury (mmHg), a unit that reflects the height of a column of mercury that can be supported by the pressure. Maintaining a blood pressure around 120/80 mmHg is important for overall cardiovascular health and reduces the risk of conditions like hypertension and heart disease.