| A celestial body of the solar system, revolving around the sun in a nearly circular orbit, or a similar body revolving around a star. The larger of such bodies are sometimes called "principal planets" to distinguish them form asteroids, planetoids, or minor planets, which are comparatively very small. An inferior planet has an orbit smaller than that of the earth: a superior planet has an orbit larger than that of the earth. The four planets nearest the sun are called "inner planets"; the others, "outer planets". The four largest planets are called "major planets". The word "planet" is of Greek origin meaning, literally, wanderer, applied because the planets appear to move relative to the stars.
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