n.1 an unfilled space or interval; a blank; a break in continuity.
2 a breach in a hedge, fence, or wall.
3 a wide (usu. undesirable) divergence in views, sympathies, development, etc. (generation gap).
4 a gorge or pass.
Phrases and idioms:
fill (or close etc.) a gap make up a deficiency. gap-toothed having gaps between the teeth.
Derivatives:
gapped adj. gappy adj.
Etymology: ME f. ON, chasm, rel. to GAPE