Any design using a combination of mirrors and lenses. Catadioptics are typically smaller than other designs of similar focal length as the fold the light path or a telescope by reflecting it back and forth.. The popular Schmidt-Cassegrain (SCT) and Maksutov-Cassegrain designs are common examples of catadioptic designs.

A telescope using both mirrors and lenses to focus light. The most popular of these is the Schmidt-Cassegrain telescope.

a special type of reflecting telescope that possesses a correcting lens at the top to form the image