walled plain

American  

noun

1. a circular or almost circular area on the moon, sometimes with a floor that is depressed, usually partially enclosed by walls that rise to varying heights and that are usually lower than those of a crater.

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walled plain British  

noun

1. any of the largest of the lunar craters, having diameters between 50 and 300 kilometres

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Example Sentences

Usually the floor of a walled plain becomes brighter as the sun rises higher and higher in the sky, but Plato actually becomes darker under a high sun.

From To Mars via The Moon An Astronomical Story by Wicks, Mark

PHOCYLIDES.—This extraordinary walled plain, with its neighbouring enclosures, is structurally very remarkable and suggestive.

From The Moon A Full Description and Map of its Principal Physical Features by Elger, Thomas Gwyn

That," I said, "is a large walled plain called Plato, and, being on a receding curve of the moon, it is seen from the earth foreshortened, so that it appears to be elliptical in shape.

From To Mars via The Moon An Astronomical Story by Wicks, Mark

The above comprise all the mountain ranges in the northern hemisphere of any prominence, or which have received distinctive names, except the Hercynian Mountains, on the north-east limb, east of the walled plain Otto Struve.

From The Moon A Full Description and Map of its Principal Physical Features by Elger, Thomas Gwyn

PONTECOULANT.—A great irregular walled plain, about 100 miles in length, near the S.W. limb, with a border rising in places to a height of 6000 feet above the floor.

From The Moon A Full Description and Map of its Principal Physical Features by Elger, Thomas Gwyn