noun (n)

• (biology) the structural adaptation of some body part for a particular function(noun.process)

  Synonym:
  differentiation, specialization
  

  source: wordnet30
• the act of specializing; making something suitable for a special purpose(noun.act)

  Synonym:
  specialization
  

  source: wordnet30
• the special line of work you have adopted as your career(noun.act)

  Synonym:
  specialism, speciality, specialization, specialty
  

  source: wordnet30