power of appointment

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

• noun Authority enabling a person to dispose of a decedent's property.

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

• noun law In the law of wills, the ability of a testator to select a person who will be given the authority to dispose of certain property under the will.

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

• noun authority given (in a will or deed) by a donor to a donee to appoint the beneficiaries of the donor's property