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Areography, ā-re-ō′gra-fi, n. description of the physical features of the planet Mars.

In 1659, Huyghens laid the foundation stone of areography by observing some dark spots, and determining from their apparent movements that the planet had a rotation on its axis, which it accomplished in about the same time as the Earth.

Gradually, as telescopes improved and observers increased in number, the principal features of the planet were disclosed and charted, and ``areography,'' as the geography of Mars was called, took its place among the recognized branches of astronomical study.

But it was not before 1877 that a fundamentally new discovery in areography gave a truly sensational turn to speculation about life on ``the red planet.''