Oath

Oath, sworn statement, affirmation, or pledge, usually based upon religious principles and often used in legal matters. In a court of law, for example, every witness must swear or affirm that the testimony he or she gives is the truth. Another example is the oath taken by a public official, such as the president or vice president of the United States, when that official assumes office. Aliens take an oath of allegiance when they become naturalized citizens. The taking of an oath generally implies some legal or moral sanction for failing to carry out one's sworn pledge; a trial witness, for instance, may be charged with the crime of perjury for lying while under oath.

The oath has its origins in religious customs, and some form of binding oath can be found in every culture. Oaths are administered to those entering such institutions as the military, secret societies, religious orders, and marriage.