casing

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An outer cover.
• noun The frame or framework for a window or door.
• noun A metal pipe or tube used as a lining for a water, oil, or gas well.
• noun A membranous case, often made of animal intestine, used to contain sausage or other processed meat.
• noun A narrow passage for a rod or cord, as in a curtain or the waistband of a garment, made by folding over a small strip of fabric at its edge along its width and sewing it in place.

from The Century Dictionary.

• noun The process of putting tobacco leaf into the desired ‘case’ or condition, namely by moistening, and adding the ingredients used to give flavor, etc. See case, n., 9.
• noun The act or process expressed by the verb case.
• noun A case; a covering; an inclosure.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act or process of inclosing in, or covering with, a case or thin substance, as plaster, boards, etc.
• noun An outside covering, for protection or ornament, or to precent the radiation of heat.
• noun An inclosing frame; esp. the framework around a door or a window. See Case, n., 4.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun That which encloses or encases.
• noun uncountable, computing The collective states of upper and lower case letters.
• verb Present participle of case.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the housing or outer covering of something
• noun the outermost covering of a pneumatic tire
• noun the enclosing frame around a door or window opening