Which term refers to a covering over the coronet band of the horse?

The term that refers to a covering over the coronet band of the horse is the coronet itself. The coronet is the region at the top of the hoof, where the hoof wall meets the skin. It plays an important role in the growth of the hoof, as it is where the hoof wall is produced. A covering over this area typically indicates an extension of the coat or may refer to markings that appear around this part of the horse.

In contrast, the other options describe different concepts related to markings or parts of a horse's leg. A sock refers to white markings that cover the lower portion of a horse's leg, while a half pastern indicates markings that extend up the leg but do not reach the knee or hock. A snip is specifically a white marking found on the nose of a horse, making it distinct from the coronet, which is the area at the top of the hoof. Thus, the designation of the coronet as the covering over the coronet band accurately captures its significance and function.