evidence
The term theory is used differently in science than it is used in everyday language. A scientific theory is a broad explanation that is widely accepted because it is supported by a great deal of evidence. Because it is so well supported, a scientific theory has a very good chance of being a correct explanation for events in nature. Because it is a broad explanation, it can explain many observations and pieces of evidence. In other words, it can help connect and make sense of many phenomena in the natural world.