demonstrator
n. B2 Upper Intermediate US //ˈdɛmənˌstɹeɪtɝ// UK //dˈɛmənstɹˌeɪtɐ// demon·stra·tor
n. a person who shows how to use a product or explains a process. You often see them at a store or a fair to help customers understand a new machine.
n. a person who exhibits or explains the use of a product, process, or theory. Often used in commercial or educational contexts to provide a visual or practical example.
The demonstrator showed us how to use the new camera.
At the electronics fair, a professional demonstrator explained the features of the latest smart home system to potential buyers.
The lead demonstrator walked the audience through the assembly process, ensuring that each step was clear before moving on to the next stage of the workshop.
From demonstrate + -or.