What are Altocumulus and Altostratus clouds?

The term Altocumulus generally refers to medium Cloud that consists of a mass of small, relatively thin, globular patches, may be so close together that their edges join each other. Altostratus refers to medium Cloud in the form of a continuous sheet or veil, that is thin or so thick as completely to obscure the sun or moon. Normally the sun or moon shines through it with a gleam. It resembles thick Cirrostratus cloud, but gives no halo with sun or moon. Being associated with the approach of a Depression, it presages a period of rain.