Hi Echofolating :) In spoken language, I think people use these two terms interchangeably. The word "serial" though, refers specifically to a plot, or story, that develops over a number of different episodes. Technically speaking, Game of Thrones, is a serial. A TV series, doesn't necessarily have a developing plot, but it may have the same characters, doing similar activities over time -- and it may involve an element of growth. The Simpsons is an animated TV series, because every episode has a different self-conclusive plot. I hope this helps. a

I believe that "serial" is more common in G. Britain, while the usage of "series" is pretty much universal in USA.

A serial is one story broken into different episodes. In a series each episode is usually a different story but the characters are the same. "Soap operas are a popular type of TV serial." "Friends is a well-known TV series."