Case

1. A small fissure, admitting water into the mine workings.
2. One of the frames, of four pieces of plank each, placed side by side to form a continuous lining in galleries run in loose earth. Webster 2nd
3. To line a borehole with steel tubing, such as casing or pipe. Syn: case in
4. In a ferrous alloy, the outer portion that has been made harder than the inner portion, or core, by casehardening. ASM, 1

Source: Dictionary of Mining, Mineral, and Related Terms