Verb
1. assign a label to; designate with a label;
"These students were labelled `learning disabled'"2. attach a tag or label to;
"label these bottles"3. pronounce judgment on;
"They labeled him unfit to work here"4. distinguish (as a compound or molecule) by introducing a labeled atom
5. distinguish (an element or atom) by using a radioactive isotope or an isotope of unusual mass for tracing through chemical reactions