ive heard this term used before ...could some help explaining the meaning and possibly and how to correct
Hook is when the trailing edge of the bottom of the hull "hooks" down into the water further than the few feet of the bottom just ahead of it. You can check it with a 4' straightedge.
Hook in general tends to bring the bow down, causing more wetted area (i.e. friction) and slows the boat down.
If you do a search for "bottom blueprinting", "hook", "rocker" (which is the opposite of hook) you will find quite a few threads on guys who have tried to fix the hook in their hulls with varying results. There is more to it than meets the eye!