What is a 'spec script'?

What is a 'spec script'?

Pamela Douglas (Screenwriter) gives expert video advice on: How do I know if my idea will make a great TV drama?; How many pages is a TV drama script?; What do I do if my script is running long? and more...

A spec script is a speculative piece of writing which you have done without a commission and without being paid, in order to demonstrate your skill. Usually it's an episode for an existing series.