gap

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An opening in a solid structure or surface; a cleft or breach: wriggled through a gap in the fence; a large gap in the wall where the artillery shell had exploded.
2. n. A break in a line of defense.
3. n. An opening through mountains; a pass.
4. n. A space between objects or points; an aperture: a gap between his front teeth.
5. n. An interruption of continuity: a nine-minute gap in the recorded conversation; needed to fill in the gaps in her knowledge.
6. n. A conspicuous difference or imbalance; a disparity: a gap between revenue and spending; the widening gap between rich and poor.
7. n. A problematic situation resulting from such a disparity: the budget gap; the technology gap.
8. n. A spark gap.
9. n. Computer Science An absence of information on a recording medium, often used to signal the end of a segment of information.
10. n. Electronics The distance between the head of a recording device and the surface of the recording medium.
11. v. To make an opening in.
12. v. To be or become open.

Century Dictionary and Cyclopedia

1. n. A break or opening, as in a fence, a wall, or the like; a breach; a chasm; a way of passage, as between rocks or through a mountain; a vacant space.
2. n. Specifically A deep sloping ravine, notch, or cleft cutting a mountain-ridge. The term is especially common in the central portion of the Appalachian range, where such openings are of frequent occurrence and are important features in the topography. The principal gaps have specific names, as Manassas Gap and Thoroughfare Gap in Virginia. Where such a gap is a through cut, penetrating to the mountain's base, and giving passage, as it then usually does, to a stream, it is called a water-gap, as the Delaware Water-gap in Pennsylvania; when it indents only the upper part of the ridge, it is called a wind-gap. See notch.
3. n. In general, any hiatus, breach, or interruption of consecutiveness or continuity: as, a gap in an argument.
4. n. See the extract, and break-lathe.
5. To notch or jag; cut into teeth like those of a saw.
6. To make a break or opening in, as a fence, a wall, or any mass of matter.
7. To cause a hiatus of any kind in; cause to lose consecutiveness or continuity.

Wiktionary

1. n. An opening in anything made by breaking or parting.
2. n. An opening allowing passage or entrance.
3. n. An opening that implies a breach or defect.
4. n. A vacant space or time.
5. n. A hiatus.
6. n. A mountain or hill pass.
7. n. Sussex A sheltered area of coast between two cliffs (mostly restricted to place names).
8. n. baseball The regions between the outfielders.
9. n. Australia The shortfall between the amount the medical insurer will pay to the service provider and the scheduled fee for the item.
10. v. transitive To notch, as a sword or knife.
11. v. transitive To make an opening in; to breach.
12. v. To check the size of a gap.

GNU Webster's 1913

1. n. An opening in anything made by breaking or parting; ; 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.
2. n. (Aëronautics) The vertical distance between two superposed surfaces, esp. in a biplane.
3. v. To notch, as a sword or knife.
4. v. To make an opening in; to breach.

WordNet 3.0

1. n. a difference (especially an unfortunate difference) between two opinions or two views or two situations
2. n. an act of delaying or interrupting the continuity
3. n. a pass between mountain peaks
4. n. a narrow opening
5. v. make an opening or gap in
6. n. an open or empty space in or between things
7. n. a conspicuous disparity or difference as between two figures