What is the meaning of Witness?

Attestation of a fact or event; testimony.

One who sees or has personal knowledge of something.

Someone called to give evidence in a court.

One who is called upon to witness an event or action, such as a wedding or the signing of a document.

Something that serves as evidence; a sign or token.

To furnish proof of, to show.

To take as evidence.

To see or gain knowledge of through experience.

To present personal religious testimony; to preach at (someone) or on behalf of.

To see the execution of (a legal instrument), and subscribe it for the purpose of establishing its authenticity.

Source: wiktionary.org