specialization

Noun

• (biology) the structural adaptation of some body part for a particular function
  • cell differentiation in the developing embryo
    

• the special line of work you have adopted as your career
  • his specialization is gastroenterology
    

• the act of specializing; making something suitable for a special purpose

Related words

• Synonyms: 
  specialisation , differentiation , specialty , speciality , specialism