specialist specialist /ˈspɛʃəlɪst/

noun

1. () An expert who is devoted to one occupation or branch of learning  ( specialiser [British] , specializer , specialist )
   an expert who is devoted to one occupation or branch of learning
     The medical specialist focused on a specific area of expertise, providing specialized care.
   The medical specialist focused on a specific area of expertise, providing specialized care.
   
   
2. () Practices one branch of medicine  ( medical specialist , specialist )
   practices one branch of medicine
   

 IR IR /ɪr/

noun

1. [UK] A board of the British government that administers and collects major direct taxes  ( Inland Revenue [UK] , IR [UK] )
   a board of the British government that administers and collects major direct taxes
   

 Ir

1. A heavy brittle metallic element of the platinum group; used in alloys; occurs in natural alloys with platinum or osmium  ( atomic number 77 , Ir , iridium )
   a heavy brittle metallic element of the platinum group; used in alloys; occurs in natural alloys with platinum or osmium
   
   

 Otto Jespersen Otto Jespersen /ˈɔtoʊ ˈjɛspərsən/

noun

1. Danish linguist (1860-1943)  ( Jens Otto Harry Jespersen , Jespersen , Otto Jespersen )
   Danish linguist (1860-1943)
   
   

 emcee emcee /ˈɛmˈsiː/

noun

1. [ N. American] A person who acts as host at formal occasions (makes an introductory speech and introduces other speakers)  ( emcee [ N. American] , master of ceremonies , host )
   a person who acts as host at formal occasions (makes an introductory speech and introduces other speakers)
    The host gracefully introduced each guest speaker at the event.
   The host gracefully introduced each guest speaker at the event.
   
   

verb

1. [ N. American] Act as a master of ceremonies  ( compere [British] , emcee [ N. American] , compère )
   act as a master of ceremonies