DEMONSTRATOR
demonstrator, protester
(noun) someone who participates in a public display of group feeling
demonstrator, sales demonstrator
(noun) someone who demonstrates an article to a prospective buyer
demonstrator
(noun) a teacher or teacher’s assistant who demonstrates the principles that are being taught
Source: WordNet® 3.1
Etymology
Noun
demonstrator (plural demonstrators)
One who demonstrates anything, or proves beyond doubt.
The forefinger.
One who takes part in a demonstration; a protester.
One who demonstrates products in a retail environment; a merchandiser.
An item, particularly a vehicle, used in demonstrations to a customer or user.
An assistant to a lecturer.
One who teaches anatomy from the dissected parts.
Synonyms
• See index finger
Source: Wiktionary
Dem"on*stra`tor, n. Etym: [L.: cf. F. démonstrateur.]
1. One who demonstrates; one who proves anything with certainty, or
establishes it by indubitable evidence.
2. (Anat.)
Definition: A teacher of practical anatomy.
Source: Webster’s Unabridged Dictionary 1913 Edition