Timing is all about periodicity; if something beeps every second, you can measure intervals between two beeps but have no other information. It's often the case that timing is also synchronized to, say, second boundaries too, and most time sources would do this. Time would then be giving some indices to those beeps; the time source would beep and say that it was the N-th beep so that you can work the actual time out from N.

I assume they are referring to the channel timing? Cellular frequencies are segmented into time segments where each channel is allowed to be used by only some devices when it is their "turn" to transmit (this allows multiple phones to share the same frequency at the same time).