Literally means timing reference. For example, on a typical watch the time base is in seconds. In music/video/film production it pertains to synchronization and has roughly the same meaning, though the units are often frames. The time base is the timing reference to which things are synchronizing. For example, in many video houses the time base is black burst or house sync. In a digital audio setup the time base is often word clock at the sample rate. An important and sometimes cloudy issue in complex synchronization scenarios is which device is acting as the time base master and what is slaving to it. Only one device can be a time base master and it’s extremely important for all other synced devices to slave to it. A time base ONLY controls the overall timing of the system. It does not have anything to do with location or transport control. It is generally best to have the most stable and high-resolution device be the time base master. That’s why video houses have used black burst and why digital systems derive everything from a stable word clock source.