A terabyte is a unit of digital information, meaning one trillion bytes.
A byte, in turn, is made up of eight bits, which are the most basic unit of information in computing. A byte is a group of bits that store data and execute instructions.
Bit is short for binary digit, which means that it can only have one of two values, 0 or 1.
A terabyte could fit approximately 500 hours of video. Taking the assumption that films are roughly 120 minutes long, that would mean around 250 films.