noun
celebrant
SEL-ih-brunt/ˈselɪbrənt/
A participant in a formal celebration.
The celebrant addresses the gathered family during the outdoor naming ceremony.

Etymology
Latin celeber meant crowded or well-attended, and its verb developed the sense of assembling to honor. A celebrant is someone carrying out that honoring, whether officiating at a ceremony or joining a celebration.
In context
he was the celebrant of the mass and nobody there had ever heard of him before so nobody knew what to expect and I had an inkling that he would give a fiery sermon
More examples
- The priest serves as celebrant at Mass.
- Cheering celebrants fill the square after the victory.
- The festival's celebrants gather beside the river.
Forms
celebrant · celebrants
Similar words
- officiant
- Specifically conducts a ceremony rather than merely participating.
- reveler
- Usually participates in lively or noisy festivities.