Petroglyphs

Petroglyphs are images created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions of the technique to refer to such images. Petroglyphs are found world-wide, and are often associated with prehistoric peoples. The word comes from the Greek word petro-, theme of the word "petra" meaning "stone", and glyphein meaning "to carve", and was originally coined in French as pétroglyphe.

The term petroglyph should not be confused with petrograph, which is an image drawn or painted on a rock face. Both types of image belong to the wider and more general category of rock art or parietal art. Petroforms, or patterns and shapes made by many large rocks and boulders over the ground, are also quite different. Inukshuks are also unique, and found only in the Arctic (except for reproductions and imitations built in more southerly latitudes).

A more developed form of petroglyph, normally found in literate cultures, a rock relief or rock-cut relief is a relief sculpture carved on solid or "living rock" such as a cliff, rather than a detached piece of stone. They are a category of rock art, and sometimes found in conjunction with rock-cut architecture. However, they tend to be omitted in most works on rock art, which concentrate on engravings and paintings by prehistoric peoples. A few such works exploit the natural contours of the rock and use them to define an image, but they do not amount to man-made reliefs. Rock reliefs have been made in many cultures, and were especially important in the art of the Ancient Near East. Rock reliefs are generally fairly large, as they need to be to make an impact in the open air. Most have figures that are over life-size, and in many the figures are multiples of life-size.

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