noun

• a brief description given for purposes of identification
  "the label Modern is applied to many different kinds of architecture"
• trade name of a company that produces musical recordings
  "the artists and repertoire department of a recording label is responsible for finding new talent"
• a radioactive isotope that is used in a compound in order to trace the mechanism of a chemical reaction
• an identifying or descriptive marker that is attached to an object

verb

• assign a label to; designate with a label
  "These students were labelled `learning disabled'"
• attach a tag or label to
  "label these bottles"
• pronounce judgment on
  "They labeled him unfit to work here"
• distinguish (as a compound or molecule) by introducing a labeled atom