GAP

vt to notch, as a sword or knife.

2. gap ·vt to make an opening in; to breach.

3. gap ·add. ·noun the vertical distance between two superposed surfaces, ·esp. in a biplane.

4. gap ·noun 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.