What are the differences between a "hypothesis" and a "theory"?

Hello!
A hypothesis is a tentative explanation of an observation that can be tested. It acts as a starting point for further explanation. Theory, on the other hand, is an explanation of some aspect of the natural world that’s well-justified by facts, tested hypotheses, and laws. 
In other words, a hypothesis is based on limited data and has an uncertain outcome, whereas a theory is based on extensive data and has a certain outcome.  A hypothesis can either be right or wrong. When a hypothesis is tested and proved true, it becomes a theory.