A more thorough explanation:

A fact is something that is true and can be proven. It is an event that actually happened or a statement that is presented as objective truth. In a court of law, determining the facts is very important.

• The sky is blue.
• George Washington was the first president of the United States.
• The earth revolves around the sun.

These examples are all facts because they are true and can be proven. The sky is blue can be proven by looking up at the sky on a clear day. George Washington being the first president of the United States can be proven by looking at historical documents. The earth revolving around the sun can be proven by scientific evidence.