"MISCONCEPTION: Evolution is ‘just' a theory.
CORRECTION: This misconception stems from a mix-up between casual and scientific use of the word theory. In everyday language, theory is often used to mean a hunch with little evidential support. Scientific theories, on the other hand, are broad explanations for a wide range of phenomena. In order to be accepted by the scientific community, a theory must be strongly supported by many different lines of evidence. Evolution is a well-supported and broadly accepted scientific theory; it is not ‘just' a hunch."
This misconception was quoted from [http://evolution.berkeley.edu/evolibrary/misconceptions_teacherfaq.php#e2].
I find it interesting how many of my students think of theories in this same light. This is a great video to include when discussing the "theory of evolution". This short video compares evolution with other theories that are widely accepted.