A collective noun names a group of people, animals or things.
Example: class, crew, team, crowd, choir
In the following story there are some bold collective nouns:
The real richness
One day, a rich man wanted to show his son how the poor lived, so he could be grateful for his wealth. He spent three days with a poor family. On their way back home , the healthy man asked his son, “How was it?, What did you learn? The boy answered, I saw that we have a bunch of servants that serve us but they serve others. I also saw that we have only one dog but they have a pack of dogs. We have expensive lanterns in our garden but they have a galaxy of stars at night. We buy our food but they grow their own. We have a large pool but they have a river with a school of fish and more animals. We have big walls that protect us but they have an army of friends to protect them. Finally , the boy said” thanks father for showing me how poor we are”
As a general rule: British people tend to use collective nouns as plural and Americans tend to use them as singular. E.g. The jury have not reached a conclusion, because they are still arguing. The jury has delivered its conclusion to the judge.