altitude (thing)

In casual reference, this is the same as elevation. This is the vertical distance from the average sea level to your point.

As you rise in altitude, for example, traveling from Los Angeles (~0ft altitude) to Denver (~5000ft) certain environmental factors change:

• Air pressure drops. This makes high-altitude cooking a challenge, and causes containers to bulge. Your shampoo bottles will spurt all over the clothes in your suitcase, and your bags of potato chips will bulge, unless you are in a market where the snack companies take countermeasures. Even more interesting are marshmallows -- they grow HUGE!
• Air density drops. Because of the lower density of air, air-inductors will not work as you expect. You require greater amounts of air for cooling and combustion. Cooling fans must be larger, and car engines must flow more air. Vacuume cleaners are less effective.
• Radiation increases. As the atmosphere thins, there is less mass to protect the surfaces from cosmic and other radiation. High density computer chips may suffer tiny failures more often. Sunburn is also a larger problem.

See high-altitude cooking and cosmic rays