Affirmation

Affirmation is a process, an action, or the fact of being affirmed. It involves stating, asserting, supporting, defending or upholding of a fact. Though affirmation is a formal action, it does not involve taking an oath to testify a truth, especially in a court.

As a legal term, it is simply a formal declaration, which is treated as admissible, especially in cases in which declaration are made by people who believe in their conscience rather than taking oath, and due to this reason they decline to take oath.