Is there a specific term for the short descriptions of a movie or TV episode present in TV guides?

Solution 1:

It could be called a synopsis

3 a brief summary of the plot of a novel, motion picture, play, etc.

Solution 2:

This is the blurb.

Originally the term used for a brief description of a book printed on its back cover to entice browsers to purchase it. The term is now widely used for short promotional descriptions of films, television programmes and other media.