extracellular fluid

n.
  1. The interstitial fluid and the plasma, constituting about 20 percent of the weight of the body.
  2. All fluid outside of cells, usually excluding transcellular fluid.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.