blood plasma

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The pale yellow or gray-yellow, protein-containing fluid portion of the blood in which the blood cells and platelets are normally suspended.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun hematology The clear fluid portion of blood in which the red blood cells, white blood cells and platelets are suspended; forms serum upon clotting.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the colorless watery fluid of the blood and lymph that contains no cells, but in which the blood cells (erythrocytes, leukocytes, and thrombocytes) are suspended