label [ME, band] , 1. n., a substance with a special affinity for an organ, tissue, cell, or microorganism in which it may become deposited and fixed. 2. n., an atom or molecule attached to either a ligand or binding protein and capable of generating a signal for monitoring in the binding reaction. 3. v., to deposit and fix a substance, tissue, cell, or microorganism. 4. v., to attach a radioisotope to a compound for the purpose of tracing it during a physiological action in the body. 5. a word or phrase that describes or identifies something or someone.
