witness

A witness is a person who has observed an event or has knowledge of relevant facts and is called to provide information about them, typically through sworn testimony or a written statement. The verb to witness means to attest or bear testimony to a fact or event.

In legal contexts, witnesses offer testimony in court or other proceedings. Eyewitnesses describe what they directly observed; expert witnesses provide specialized knowledge such as forensics or medicine; lay witnesses may report other factual observations. Testimony is usually given under oath or affirmation and may be subject to cross-examination. Written statements, including depositions and affidavits, can also serve as evidence. Hearsay, or statements about what someone else said, is generally restricted unless an exception applies.

Outside the courtroom, the term is used more broadly to describe someone who bears witness to events or beliefs. Religions may speak of bearing witness to faith or truth; journalists or ordinary individuals who witness events can influence public understanding through their accounts. The phrase to bear witness emphasizes testimony to truth and accountability across cultures and legal systems.

Etymology traces the word to Old English witnes, related to wit and knowledge, with roots in Proto-Germanic terms denoting knowledge or evidence. The concept highlights the role of firsthand knowledge and credibility in establishing fact and truth in both law and society.