Answer: labelling

AnswerCrossword Clue
labellingthe act of attaching a tag to
labellingMake (a substance, molecule, or cell) identifiable or traceable by replacing an atom with one of a distinctive radioactive isotope, or by attaching a fluorescent dye, enzyme, or other molecule
labellingAttach a label to (something)
labellingGive a name to (something)
labellingAssign to a category, esp. inaccurately or restrictively