demonstrator

 
Pronunciation: /ˈdɛmənstreɪtə/

noun

  • 1a participant in a public protest meeting or march: troops opened fire on crowds of demonstrators
  • 2a person who shows how a piece of equipment works or how a skill or craft is performed: the demonstrators arrived and launched into a two-hour sales pitch
  • a person who teaches by demonstration in a laboratory: she was appointed demonstrator in botany at Newnham College
  • a piece of merchandise which can be tested by potential buyers: the dealer represented the car to be new when it had been used as a demonstrator