pass (redirected from head off at the pass)

pass, opening or way by which a natural or artificial barrier can be crossed. The term pass is usually applied to a relatively narrow passage through a mountainous region. A pass, like an isthmus, may have great strategic and economic importance; the history of a nation has often been determined by its success or failure in defending a pass, and land trade routes must necessarily cross passes. In the Alps, Saint Bernard, Simplon, and Saint Gotthard are important; in the Caucasus, Daryal is traversed by a great military road; in Asia, Khyber Pass into India and the passes of the Himalayas, Karakorum, and other ranges are important.

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pass

1. a route through a range of mountains where the summit is lower or where there is a gap between peaks

2. a way through any difficult region

3. a permit, licence, or authorization to do something without restriction

4. Brit

a. the passing of a college or university examination to a satisfactory standard but not as high as honours

b. (as modifier): a pass degree

5. a dive, sweep, or bombing or landing run by an aircraft

6. a motion of the hand or of a wand as a prelude to or part of a conjuring trick

7. Sport the transfer of a ball from one player to another

8. Fencing a thrust or lunge with a sword

9. Bridge the act of passing (making no bid)

10. Bullfighting a variant of pase

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pass [pas]

(aerospace engineering)

A single circuit of the earth made by a satellite; it starts at the time the satellite crosses the equator from the Southern Hemisphere into the Northern Hemisphere.

The period of time in which a satellite is within telemetry range of a data acquisition station.

(computer science)

A complete cycle of reading, processing, and writing in a computer.

(geography)

A natural break, depression, or other low place providing a passage through high terrain, such as a mountain range.

A navigable channel leading to a harbor or river.

A narrow opening through a barrier reef, atoll, or sand bar.

(mechanical engineering)

The number of times that combustion gases are exposed to heat transfer surfaces in boilers (that is, single-pass, double-pass, and so on).

In metal rolling, the passage in one direction of metal deformed between rolls.

In metal cutting, transit of a metal cutting tool past the workpiece with a fixed tool setting.

(metallurgy)

Passage of a metal bar between rolls.

Open space between two grooved rolls through which metal is processed.

Weld metal deposited in one trip along the axis of a weld.

(mining engineering)

A mine opening through which coal or ore is delivered from a higher to a lower level.

A passage left in old workings for workers to travel as they move from one level to another.

A treatment of the whole ore sample in a sample divider.

A passage of an excavation or grading machine.

In surface mining, a complete excavator cycle in removing overburden.