Merriam-Webster's Collegiate® Dictionary, 11th Edition
WITNESS
I. noun
Etymology: Middle English witnesse, from Old English witnes knowledge, testimony, witness, from 2wit Date: before 12th century attestation of a fact or event ; testimony , one that gives evidence, one asked to be present at a transaction so as to be able to testify to its having taken place, one who has personal knowledge of something,
5. something serving as evidence or proof ; sign , public affirmation by word or example of usually religious faith or conviction , a member of the Jehovah's Witnesses,
II. verb
Date: 14th century
transitive verb to testify to ; attest , to act as legal witness of, to furnish proof of ; betoken ,
4. to have personal or direct cognizance of ; see for oneself , to take note of , to constitute the scene or time of , intransitive verb to bear witness ; testify , to bear witness to one's religious convictions , see: certify