Under-croft is a term that refers to a space or storage area, usually found below a building or structure. Some of the synonyms of under-croft include basement, cellar, substructure, foundation, sub-basement, vault, crypt, catacomb, and storage room. Each of these words has its own unique meaning, but all of them generally imply a space that is situated beneath the ground level. Some synonyms, such as vault or crypt, may also suggest a religious or historic significance. Depending on the context in which it is used, the word under-croft can be replaced by any of these synonyms to add variety and precision to a text.