What is Will?

Legal Definition
A will is a document that gives instructions for managing a testator’s estate. To be valid, a will must be in writing, signed and attested.
Legal Definition
Criminal law. The power of the mind which directs the actions of a man.

2. In criminal law it is necessary that there should be an act of the will to commit a crime, for unless the act is wilful it is no offence.

3. It is the consent of the will which renders human actions commendable or culpable, and where there is no win there can be no transgression.

4. The defect or want of will may be classed as follows: 1. Natural, as that of infancy. 2. Accidental; namely, 1st. Dementia. 2d. Casualty or chance. 3d. Ignorance. (q. v.) 3. Civil; namely, 1st. Civil subjection. 2d. Compulsion. 3d. Necessity. 4th. Well-grounded fear. Hale's P. C. c. 2 Hawk. P. C. book 1, c. 1.
-- Bouviers Law Dictionary
Legal Definition
A will is the legal expression of a man's wishes as to the disposition of his property after his death. Code Ga. 1882, § 2394; Swinb. Wilis, § 2. An instrument in writing, executed in form of law, by which a person makes a disposition of his property, to take effect utter hla death. Except where it would be inconsistent with the manifest intent of the legislature, the word "will" shall extend to a testament, and to a codicil, and to an appointment by will, or by writing in the nature of a will, in exercise of a power; and also to any other testamentary disposition. Code Va. 1887, § 2511. A will is an instrument by which a person makes a disposition of his property, to take effect after his decease, and which is, in its own nature, ambulatory and revocable during his life. It is this ambulatory quality which forms the characteristic of wills; for though a disposition by deed may postpone the possession or enjoyment, or even the vesting, until the death of the disposing party, yet the postponement is in such case produced by the express terms, and does not result from the nature of the instrument. McDaniel v. Johns, 45 Miss. 641. And see Jasper v. Jasper, 17 Or. 590, 22 Pac. 152; Leathers v. Greenacre, 53 Me. 567; Cover v. Stem, 67 Md. 449, 10 Atl. 231, 1 Am. St. Rep. 406; George v. Green, i3 N. H. 524; In re Harrison's Estate, 196 Pa. 576, 46 Atl. 888; Bayley v. Bailey, 5 Cush. (Mass.) 249; Reagan v. Stanley, 11 Lea (Tenn.) 324; Lane v. Hill, 63 N. H. 398, 44 Atl. 597; Conklin v. Eger-ton, 21 Wend. (N. Y.) 486. A wlll, when it operates upon personal property, is sometimes called a "testament," and when upon real estate, a "devise;" but the more general and the more popular denomination of the instrument embracing equally real and persona] estate is that of "last will and testament." 4 Kent, Comm. 501. In criminal law. The power of the mind which directs the action of a man. In Scotch practice. That part or clause of a process which contains the mandate or command to the officer. Bell.
See also
-- Black's Law Dictionary
Legal Definition
Any instrument, executed with the formalities required by law, whereby one makes a disposition of his property to take effect after his death. See 167 Ind. 101, 119 Am. St. Rep. 475, 77 N. E. 800.
-- Ballentine's Law Dictionary