Participant (noun)

1. A person taking part in an event or activity.
2. A person who participates in a scientific or medical trial or study.
3. A person who is entitled to share in the profits of a business or in a distribution of assets.

Origin:

Late middle english (in the sense 'partaker, sharer'): from latin participans, participantis, from the verb participare (see participate).

Examples:

1. She was a participant in the concert.
2. All participants in the study were required to provide informed consent.
3. As a shareholder, she was a participant in the company's profits.
4. The participants in the tournament were given prizes.
5. The winner of the competition was a participant from France.