A declarant, generally speaking, is anyone who composes and signs

Signature

A signature is a handwritten depiction of someone's name, nickname, or even a simple "X" that a person writes on documents as a proof of identity and intent. The writer of a signature is a signatory. Similar to a handwritten signature, a signature work describes the work as readily identifying...

 a statement

Statement

Statement may refer to:* A kind of expression in language *Statement , declarative sentence that is either true or false*Statement , the smallest standalone element of an imperative programming language...

 or declaration alleging that the information he has given therein is true

Truth

Truth has a variety of meanings, such as the state of being in accord with fact or reality. It can also mean having fidelity to an original or to a standard or ideal. In a common usage, it also means constancy or sincerity in action or character...

. This differs from an affiant, as in the case of an affidavit

Affidavit

An affidavit is a written sworn statement of fact voluntarily made by an affiant or deponent under an oath or affirmation administered by a person authorized to do so by law. Such statement is witnessed as to the authenticity of the affiant's signature by a taker of oaths, such as a notary public...

 the facts therein are sworn

Oath

An oath is either a statement of fact or a promise calling upon something or someone that the oath maker considers sacred, usually God, as a witness to the binding nature of the promise or the truth of the statement of fact. To swear is to take an oath, to make a solemn vow...

 to before an notary public

Notary public

A notary public in the common law world is a public officer constituted by law to serve the public in non-contentious matters usually concerned with estates, deeds, powers-of-attorney, and foreign and international business...

 or other official, whereas a declaration is usually made by one person for the use of another.

Uttering a statement or declaration which is proven to be false is a crime in many jurisdictions, though usually a separate offence from perjury

Perjury

Perjury, also known as forswearing, is the willful act of swearing a false oath or affirmation to tell the truth, whether spoken or in writing, concerning matters material to a judicial proceeding. That is, the witness falsely promises to tell the truth about matters which affect the outcome of the...

.

The word declarant, when discussing the hearsay

Hearsay

Hearsay is information gathered by one person from another person concerning some event, condition, or thing of which the first person had no direct experience. When submitted as evidence, such statements are called hearsay evidence. As a legal term, "hearsay" can also have the narrower meaning of...

rule and its exceptions, refers to the person who makes an out-of-court statement. For example, if John is on the witness stand and says "Mary said that she was afraid." Mary is the declarant, not John. This concept is important in understanding many applications of the hearsay rule and its exceptions.