Understair a. : Of or pertaining to the kitchen, or the servants' quarters; hence, subordinate; menial.

Example:
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Taxonomy
how to, stair, the stairs, storage, office, shelves, tutorial.

Defination from the web:
How to article - how to utilize the under-stair space. Most homes that have more than one floor have an area under the stairs that is not being utilized. If your home...