This is more broad than the main idea, usually one word

I have a dog names Boots. I taught him lots of tricks. When I tell him to, Boots will sit or lie down. He can also wave his paw to greet people. When I say, "Dance, Boots," he will stand up on two legs and walk. I don't know of many dogs that can do such amazing tricks.
What is the main idea?

These are two things needed to make an inference

This is what the passage is mostly about

Yesterday was my birthday. When I woke up, I noticed my brother Todd hung up a big sign that said, ' Happy Birthday Joey!' Mom made spaghetti for dinner. It's my favorite food in the whole world. My friend Dave came over and handed me a wrapped gift. I had a great day
What is the main idea?

This is the main reason that an author writes a passage.

These help you to identify the main idea of the passage

This is one of two places in a passage where the main idea can appear