North

North is a cardinal direction, one of the four main compass points. It lies directly opposite south and forms a right angle with east and west. The word functions as a noun, adjective, or adverb when describing direction or geography.

The term "north" traces back to the Old High German *nord*, both stemming from the Proto-Indo-European root *ner-, meaning "left" or "below." This association comes from the fact that north is to the left when facing the rising sun, and the other cardinal directions are similarly linked to the sun's position. In Latin, *borealis* derives from the Greek *boreas*, meaning "north wind" or "north," personified in Ovid as the wind-god Boreas, father of Calais and Zetes. Another Latin term, *septentrionalis*, comes from *septentriones* ("the seven plow oxen"), a name for the constellation Ursa Major. The Greek *arktikós*, also named for this constellation, gives English the word "Arctic." Other languages have different origins: in Lezgian, *kefer* can mean both "disbelief" and "north" because areas north of the Muslim Lezgian homeland were once inhabited by non-Muslim peoples. In many Mesoamerican languages, north also means "up." In Romanian, the old word for north is *mĭazănoapte*, from Latin *mediam noctem* (midnight), and in Hungarian, *észak* comes from *éjszaka* ("night"), since between the Tropic of Cancer and the Arctic Circle the sun never shines from the north. North is sometimes abbreviated as N.

By convention, the top of a map points north. To navigate north with a compass, set a bearing or azimuth of 0° or 360°. Traveling directly north follows a meridian line upward. In Western culture, north is considered the fundamental direction: it is used (explicitly or implicitly) to define all other directions. The top edges of maps usually correspond to the northern edge of the area shown, unless stated otherwise or landmarks are more useful. For any rotating astronomical object, north often denotes the side that appears to rotate counterclockwise when viewed from afar along the axis of rotation. However, the International Astronomical Union defines the geographic north pole of a planet or satellite as the pole in the same celestial hemisphere as Earth's north pole, relative to the Solar System's invariable plane. This means some objects, like Uranus, rotate retrograde: when seen from the IAU north, the spin is clockwise.

Magnetic north is the direction a properly functioning magnetic compass points. The difference between magnetic north and true north is called magnetic declination. For many purposes, ignoring this difference is acceptable; in others, compensation based on known declination solves the problem. Simple generalizations on the subject are unsound and may reflect popular misconceptions about terrestrial magnetism. Maps for orienteering by compass clearly indicate local declination for easy correction. Maps may also show grid north, the direction northward along the map projection's grid lines.

The visible rotation of the night sky around the celestial pole provides a vivid metaphor for north as "up." Thus, choosing north as "up" in the Northern Hemisphere (or south in the Southern Hemisphere) was, before global communication, not arbitrary for nighttime astronomers. (The Southern Hemisphere lacks a prominent visible analog to the northern Pole Star.) Chinese and Islamic cultures considered south the proper "top" for maps. In Polynesian cultures, where navigation was vital, winds—prevailing local or ancestral—could define cardinal points. In Western culture, maps are typically drawn with true north or magnetic north at the top. Globes have the North Pole at the top, or in the top half if the axis is inclined. Maps are usually labeled to show which direction corresponds to a direction on Earth, often with a single arrow for true north, occasionally for magnetic north, or with two arrows for both. A compass rose may appear, but usually on a map with north at the top and with north more prominently decorated. "Up" is a metaphor for north. The convention that north should be "up" and east at the right was established by the Greek astronomer Ptolemy. Historian Daniel Boorstin suggested this may be because better-known places in his world were in the Northern Hemisphere, making them most convenient for study in the upper right-hand corner of a flat map. North is often associated with colder climates, as most of the world's populated high-latitude land is in the Northern Hemisphere. The Arctic Circle passes through the Arctic Ocean, Norway, Sweden, Finland, Russia, the United States (Alaska), Canada (Yukon, Northwest Territories, and Nunavut), Denmark (Greenland), and Iceland.