haematocrit

haematocrit |ˈhiːmətə (ʊ )krɪt |(US hematocrit ) ▶noun Physiology the ratio of the volume of red blood cells to the total volume of blood. • an instrument for measuring the ratio of the volume of red blood cells to the total volume of blood, typically by centrifugation. ORIGIN late 19th cent.: from haemato- ‘of blood ’ + Greek kritēs ‘judge ’.