The Collaborative International Dictionary
extracellular \extracellular\ adj. located or occurring outside of a living cell or cells; as, extracellular fluid. Opposite of intracellular.
Wiktionary
a. occurring or found outside of a cell
WordNet
adj. located or occurring outside a cell or cells; "extracellular fluid" [ant: intracellular]
Wikipedia
In cell biology, molecular biology and related fields, the word extracellular (or sometimes extracellular space) means "outside the cell". This space is usually taken to be outside the plasma membranes, and occupied by fluid (see extracellular matrix). The term is used in contrast to intracellular (inside the cell).
According to the Gene Ontology database the extracellular space is a cellular component defined as: "That part of a multicellular organism outside the cells proper, usually taken to be outside the plasma membranes, and occupied by fluid. For multicellular organisms, the extracellular space refers to everything outside a cell, but still within the organism (excluding the extracellular matrix). Gene products from a multi-cellular organism that are secreted from a cell into the interstitial fluid or blood can therefore be annotated to this term".
The composition of the extracellular space includes metabolites, ions, various proteins and non-protein substances (i.e. DNA, RNA, lipids, microbial products etc.) that might affect cellular function. For example, hormones, growth factors, cytokines and chemokines act by travelling the extracellular space towards biochemical receptors on cells. Other proteins that are active outside the cell are various enzymes, including digestive enzymes ( Trypsin, Pepsin), extracellular proteinases ( Matrix metalloproteinases, ADAMTSs, Cathepsins) and antioxidant enzymes (extracellular superoxide dismutase). Often, proteins present in the extracellular space are stored outside the cells by attaching to various Extracellular matrix components ( Collagens, Proteoglycans, etc.). In addition, Extracellular matrix proteolytic products are also present in the extracellular space, especially in tissues undergoing remodelling [2].
Usage examples of "extracellular".
In living tissue, sodium ion is to be found almost entirely outside the cells in the extracellular fluid.
Then came a bump on the screen as the cells contracted while the cytoplasmic organelles worked like crazy to pump the ions back into the extracellular fluid.
At the same time the cocaine began to diffuse out of the coronary vessels into the extracellular fluid, bathing the hardworking heart muscle fibers.
What you just did was press the extracellular water out of that spot, and it will take a little time for it to go back to being smooth.
Then again beta-amyloid protein accumulated in the cerebral blood vessels and in the extracellular space around nerve terminals, again impeding function.