Dolby is a company that creates sound and picture technologies for TVs, cinemas, and streaming.
On TVs, you’ll often see Dolby Vision (advanced HDR for brighter colors and better contrast) and Dolby Atmos (3D surround sound that feels like sound is moving around you).
For example, with Dolby Atmos, a plane flying overhead in a movie feels like the sound is coming from above your head, not just from the TV speakers.
See also: HDR, Dolby Vision, Dolby Atmos, Surround Sound.