A high-speed data transfer wire and port for a computer (stands for "Universal Serial Bus"). USB 1 is slower than Firewire 400, but USB 2 is faster than Firewire 400 and slower than Firewire 800.

NB: While USB 2 is technically faster than Firewire 400, Firewire has a consistent data stream that may preform better than USB for jobs like video editing. This is why many editors reject external USB hard drives. In my experience USB works fine under most conditions.