Okla. Stat. tit. 60, § 60-751

As used in this act, unless otherwise clearly required by the

context:

1. "Beneficiary" means and includes any person entitled, but

for his disclaimer, to take an interest, as grantee; as donee; under

any assignment or instrument of conveyance or transfer; by

succession to a disclaimed interest, other than by will, intestate

succession or through the exercise or nonexercise of a testamentary

power of appointment; as beneficiary of an inter vivos trust or

insurance contract; pursuant to the exercise or nonexercise of a

nontestamentary power of appointment; as donee of a power of

appointment created by a nontestamentary instrument; or otherwise

under any nontestamentary instrument;

2. "Interest" means and includes the whole of any property,

real or personal, legal or equitable, or any fractional part, share

or particular portion or specific assets thereof or any estate in

any such property including but not limited to a joint tenancy

interest in any such property, or power to appoint, consume, apply

or expend property or any other right, power, privilege or immunity

relating thereto; and

3. "Disclaimer" means a written instrument which declines,

refuses, releases or disclaims an interest which would otherwise be

succeeded to by a beneficiary, which instrument defines the nature

and extent of the interest disclaimed thereby and which must be

signed, witnessed and acknowledged by the disclaimant in the manner

provided for deeds of real estate.