Oath

Traditionally an oath (from Anglo-Saxon āð, also called plight) is either a statement of fact or a promise with wording relating to something considered sacred as a sign of verity. A common legal substitute for those who conscientiously object to making sacred oaths is to give an affirmation instead. Nowadays, even when there's no notion of sanctity involved, certain promises said out loud in ceremonial or juridical purpose are referred to as oaths. To swear is a verb used to describe the taking of an oath, to making a solemn vow.