Bitcoin is a form of digital currency, created and held electronically. No one controls it. Bitcoins arenâ€™t printed, like dollars or euros â€“ theyâ€™re produced by people, and increasingly businesses, running computers all around the world, using software that solves mathematical problems.
Itâ€™s the first example of a growing category of money known as cryptocurrency.
Here is a playlist with some videos explaining it indepth: