What does ERRO stand for? 

Erro

Erro is a lunar crater that lies beyond the eastern limb of the Moon, on the far side as seen from the Earth. It lies along the eastern fringes of the uneven plain that joins Mare Marginis to the northwest with Mare Smythii to the west-southwest. This part of the surface is sometimes brought into sight of observers on the Earth due to libration. However even at such times not much detail can be seen, as the surface is viewed from the edge. Nearby craters of note include Babcock to the west-southwest, Saenger to the east-southeast, and Dreyer to the north-northwest. This crater has a low, broken rim that only projects a small distance above the surface. The somewhat uneven surrounding plains have intruded into the interior of this crater, leaving a level, nearly featureless floor. The most intact sections of the rim lie along the northern and northeastern sides. The satellite crater Erro V is attached to the outer rim to the northwest, and there is a smaller crater along the southern rim. There is a small craterlet in the northeastern part of the interior floor.

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