It's valley speak for time. It annoys the hell out of me but I don't have the bandwidth to complain every time. :/
Sorry to be off topic here, but I'd argue it's more involved than "time". Bandwidth, in network terms, has to do with throughput over a specified link, which does have time in its denominator (bits per second, for instance). So the analogy is that you have a limited amount of work throughput, and you can't fit the additional task within that time slot. I don't know that it's entirely inaccurate, but maybe that's not what annoys you about it.
A more direct analogy to just "time" would be latency, which is how quickly you could get the task done. And I don't think that's what AmpedRealtor was saying.