Labeled meaning : To put a label (a ticket or sign) on (something). (ditransitive) To give a label to (someone or something) in order to categorise that person or thing. 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. To add a detectable substance, either transiently or permanently, to a biological substance in order to track the presence of the label-substance combination either in situ or in vitro Having a label, tagged. Defined or described. Having an atom replaced by a radioactive isotope