A piece of equipment that allows video editors to insert text and graphics over the video picture or within the video frame.

Specifically, this is the brand name for a character generator sold by Chyron. It's sometimes used generically to indicate any manufacturer’s character generator.

(n) A well-known brand of character generator. The word chyron is often used generically to mean character generator. (See also super, character generator, and font). (v) To insert a chyron in the video.