Here are some options, depending on the context:
* Audience: This is the most common and general term for a group of spectators.
* Crowd: This implies a large and possibly noisy group of spectators.
* Gathering: This is more formal and suggests a group of people assembled for a specific purpose, such as a performance or event.
* Viewers: This is specific to people watching a performance or event from a distance, usually on television or a screen.
* Onlookers: This describes people who are passively observing something happening.
You can also use more specific terms, depending on the type of event:
* Congregation: For a religious gathering.
* Assembly: For a political or formal event.
* House: For a theater audience.
* Fans: For a group of people who are passionate about a particular sport or performer.
The best collective noun to use will depend on the specific context and the nuance you want to convey.