It's hard to say without a little more context, but I'd assume that it has something to do with compositing--following a tracking point in a moving camera shot, for instance, then offsetting the track from that point in order to align the composite with a different part of the image. It could also refer to using some kind of time offset, although no practical use for that springs to mind.

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Andrew Gingerich
Exploding Goldfish Films
Check out my blog at http://www.exgfilms.com
and my reel at http://portfolio.exgfilms.com

it could be...someone told me that is when the tracking point you set, move out of the frame, and the program "interpolate" the result, and go on.
I wish you can understand what I'm tring to say..my english isn't very good 🙂