LABELLING

verb

1. To put a label (a ticket or sign) on (something).
2. (ditransitive) To give a label to (someone or something) in order to categorise that person or thing.
3. To replace specific atoms by their isotope in order to track the presence or movement of this isotope through a reaction, metabolic pathway or cell.

noun

1. A set of labels applied to the various objects in a system.
2. The introduction of a traceable chemical group (e.g., containing an isotope or a fluorescent dye) into a protein or other biomolecule of interest so it can be tracked or quantified during experimental analysis.