1) Medical specialist 2) Specialist 
• (n.) A diplomatist. • (v. t.) To invest with a title o/ privilege by diploma.
Dip'lo·mate transitive verb To invest with a title or privilege by diploma. [ R.] Wood. 
[n] - medical specialist whose competence has been certified by a diploma granted by an appropriate professional group
noun medical specialist whose competence has been certified by a diploma granted by an appropriate professional group
a person who has received a diploma, esp. a doctor, engineer, etc., who has been certified as a specialist by a board within the appropriate profession.