Functionary is a term often used to describe a person who plays a role in a Toastmasters meeting or contest. Toastmasters International sometimes seems to prefer the use of the term "participant role" or meeting role  instead. Some clubs use the term "assistant" for some of the roles. Typical functionary roles may include Ah Counter, Balloter, Sergeant-at-Arms and others. Optional roles include humormaster and the person who does a moment of inspiration.
A functionary should not be confused with a dignitary.