Gap

An opening in anything made by breaking or parting; as, a gap in a fence; an opening for a passage or entrance; an opening which implies a breach or defect; a vacant space or time; a hiatus; a mountain pass.

To notch, as a sword or knife.

To make an opening in; to breach.

a difference (especially an unfortunate difference) between two opinions or two views or two situations

a conspicuous disparity or difference as between two figures; "gap between income and outgo"; "the spread between lending and borrowing costs"