A bottle episode is one continuous scene set on a single stage. The concept was originally designed to press costs during the making of expensive television shows. However, over the years it has become a modern take on the traditional one act play.
The name was first used during the production of the show Star Trek; the cast and crew would often refer to the single location episodes as “ship-in-a-bottle” episodes.
“I find television very educating. Every time somebody turns on the set, I go into the other room and read a book.” – Groucho Marx