in Logic, the asserting of the truth of any proposition.

in Law, denotes an indulgence allowed to the people called Quakers, who, in cases where an oath is required from others, may make a solemn affirmation that what they say is true; and if they make a false affirmation, they are subject to the penalties of perjury. But this relates only to oaths taken to the government, and on civil occasions; for Quakers are not permitted to give their testimony in any criminal case, &c.

AFFIRMATION is also used for the ratifying or confirming of the sentence or decree of some inferior court. Thus we say, the house of lords affirmed the decree of the chancellor, or the decree of the lords of session.