appurtenance

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

• noun Something associated with another, more important thing; an accessory. synonym: attachment.
• noun Equipment, such as clothing, tools, or instruments, used for a specific purpose or task; gear.
• noun Law A right, privilege, or property that is considered incident to the principal property for purposes such as passage of title, conveyance, or inheritance.

from The Century Dictionary.

• noun The act, state, or fact of appertaining.
• noun That which appertains or belongs to something else; something belonging to another thing as principal; an adjunct; an appendage; an accessory: as, “appurtenances of majesty,”
• noun Specifically, in law, a right, privilege, or improvement belonging to a principal property, as a right of pasture in a common attached to an estate, outhouses, gardens, etc., attached to a mansion, and the like.
• To furnish with by way of appurtenance; supply or equip.

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

• noun That which belongs to something else; an adjunct; an appendage; an accessory; something annexed to another thing more worthy; in common parlance and legal acceptation, something belonging to another thing as principal, and which passes as incident to it, as a right of way, or other easement to land; a right of common to pasture, an outhouse, barn, garden, or orchard, to a house or messuage. In a strict legal sense, land can never pass as an appurtenance to land.

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

• noun An appendage added to something else.
• noun in the plural Equipment used for some specific task; gear.
• noun The thing to which another pertains.
• noun law Minor property (such as an outhouse) that passes with the main property when it is sold.
• noun grammar A modifier that is appended or prepended to another word to coin a new word that expresses belonging.

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

• noun equipment consisting of miscellaneous articles needed for a particular operation or sport etc.
• noun a supplementary component that improves capability