The climate of a polar region; usually one that is too cold to allow the growth of trees.

An area, especially in the polar regions, having little or no vegetation due to extremely cold temperatures.

A carnivorous mammal of the dog family known for its thick, white winter coat as well as a gray phase.

Arctic adaptations include rounded ears, a short muzzle, and fur-covered footpads.

A weak high appearing on mean charts of sea-level pressure over the Arctic Basin during late spring, summer, and early autumn.

Any sea ice that is more than one year old and more than three meters thick.

Arctic or freezing air that becomes unstable, possessing a higher moisture content after passing over warmer water: Maritime polar air has comparable qualities to continental polar air, but turns out to be unpredictable when it moves across more temperate oceans or seas.

Geographical areas that are dominated by great amounts of snow and ice and also consist of vast, dry areas of polar desert because of very small amounts of rainfall: "The polar-region habitats include the Arctic and Antarctic zones with 24-hour periods of daylight in the summer and continuous darkness in the winter."

"Both polar regions provide animal life; including fish and other sea life for the polar bears, seals, penguins, etc."

A system of curvilinear coordinates (co-ordinate system composed of intersecting surfaces) in which the position of a point in space is designated by its distance from the origin or pole, called the radius vector, the angle φ between the radius vector and a vertically directed polar axis, called the cone angle or co-latitude, and the angle θ between the plane of φ and a fixed meridian plane through the polar axis, called the polar angle or longitude: The spherical coordinates are a set of coordinates used for locating a point in space, representing its distance from an origin and two angles describing its orientation relative to perpendicular axes extending from that origin.

Geographical coordinates refer to a system of coordinates for locating a point in space by the length of its radius vector and the angles this vector makes with two perpendicular polar planes.