platelet

/ˈpleɪtlɪt/
noun
  1. A tiny, disc-shaped cell in the blood that helps stop bleeding by forming clots.
    • Doctors check platelet levels in a blood test to see how well your blood clots.
    • When you get a cut, platelets rush to the wound to form a clot.
    • A low platelet count can make it hard for your body to stop bleeding.