1530s, a running (usually at full speed), a course (especially of the sun, etc., across the sky), from Middle French carriere road, racecourse (16c.), from Old ProvenÃ§al or Italian carriera, from Vulgar Latin *(via) cararia carriage (road), track for wheeled vehicles, from Latin carrus chariot (see car).
Noun. 1. tricuspid valve-valve with three cusps; situated between the right atrium and the right ventricle; allows blood to pass from atrium to ventricle and closes to prevent backflow when the ventricle contracts. right atrioventricular valve.
The problem of backflow: 1  Between each chamber of the heart are valves which prevent the blood being forced back into the chamber from which it was just pushed out. 2  The pulmonary artery and the aorta also contain valves to prevent the blood from these vessels falling back into the ventricles.