Probably everybody has heard about Sync and Genlock before but still, one can get confused by the words easily because they are often used in the wrong context or in a rather vague way.
Sync
"Sync" means that the clocks of different devices are synchronised with each other and work with the same speed. The word is often erroneously used to describe the jamming of a timecode generator to a specific time. However, this does not necessarily mean that two timecode generators work with the same speed. You can rather compare the process to two people checking and matching the time on their watches. Timecode is usually not sync!
Lockits on the other hand use a sophisticated software algorithm and wireless communication to achieve actual sync after jamming the timecode between them.
Genlock
"Genlock" describes the state of a locked Generator. This means that the clock generator of a device is locked to the speed of an external sync reference. For instance, you can control the camera shutter or sensor speed to align it with other cameras or video monitors. Often, the word Genlock is used synonymous to Tri-Level-Sync or HD-Sync, because it is the most common sync signal for achieving Genlock.