What are examples of words that plural in form but singular meaning?

You're asking about collective nouns. These words refer to a group of people or things, even though they appear to be plural. Here are some examples:

People:

* Audience

* Class

* Committee

* Crew

* Family

* Group

* Jury

* Staff

* Team

Animals:

* Flock (birds)

* Herd (cattle)

* School (fish)

* Swarm (bees)

Other:

* Data

* Information

* News

* Series

* Species

Note: Some of these words can be pluralized in certain contexts, but their singular form is most common when referring to the group as a whole. For example, you might say "The staff are all busy" if you're referring to the individual members, but you would say "The staff is working on a new project" if you're referring to the staff as a collective unit.