hematocrit
    n 1: the ratio of the volume occupied by packed red blood cells
         to the volume of the whole blood as measured by a
         hematocrit [syn: hematocrit, haematocrit, packed cell
         volume]
    2: a measuring instrument to determine (usually by
       centrifugation) the relative amounts of corpuscles and plasma
       in the blood [syn: hematocrit, haematocrit]