What is Deed Poll?

Legal Definition
A deed poll (plural: deeds poll) is a legal document binding only to a single person or several persons acting jointly to express an active intention. It is, strictly speaking, not a contract because it binds only one party and expresses an intention instead of a promise.

The most common use is a name change through a deed of change of name (often referred to simply as a deed poll). Deeds poll are used for this purpose in countries including the United Kingdom, Ireland, Hong Kong and Singapore. In the UK, a deed poll can also be used to change a child's name, as long as everyone with parental responsibility for the child consents to it and the child does not object to it. The child's parents execute the deed poll on the child's behalf. In some other jurisdictions, a person may simply start using a new name without any formal legal process. The usual requirements are that the new name must be used exclusively and that the change must not be made with intent to defraud. In Australia, name change was formerly accomplished by deed poll but now is done by completing a Change of Name form.

Another common use is to partition land into different sections. For example, a piece of land may be partitioned (or carved out) by a deed poll into Section A and the Remaining Portion thereof. This form of deed poll is commonly used in Hong Kong.

A deed poll may also be used (in England and Wales) for clergy of the Church of England to relinquish their holy orders.
-- Wikipedia
Legal Definition
Contracts. A deed made by one party only is not indented, but polled or shaved quite even, and is, for this reason, called a deed poll, or single deed. Co. Litt. 299, a.

2. A deed poll is not, strictly speaking, an agreement between two persons; but a declaration of some one particular person, respecting an agreement made by him with some other person. For example, a feoffment from A to B by deed poll, is not an agreement between A and B, but rather a declaration by A addressed to all mankind, informing them that he thereby gives and enfeoffs B of certain land therein described.

3. It was formerly called charta de una parte, and, usually began with these words, Sciant praesentes et futuri quod ego A, &c.; and now begins, "Know all men by these presents, that I, A B, have given, granted, and enfeoffed, and by these presents do give, grant and enfeoff," &c. Cruise, Real Prop. tit. 32, c. 1, s. 23.
-- Bouviers Law Dictionary
Legal Definition
In conveyancing. A deed of one part or made by one party only; and originally so called because the edge of the paper or parchment was polled or cut in a straight line, wherein it was distinguished from a deed indented or indenture. As to a special use of this term in Pennsylvania in colonial times, see Herron v. Dater, 120 U. S. 464, 7 Sup. Ct. 620, 30 L. Ed. 748
-- Black's Law Dictionary
Legal Definition
A single deed, not indented.
-- Ballentine's Law Dictionary