Meaning

noun someone who sees an event and reports what happened

noun a close observer; someone who looks at something (such as an exhibition of some kind)

noun testimony by word or deed to your religious faith

originFrom Middle English witnesse, from Old English ġewitnes, equivalent to wit + -ness. Cognate with Middle Dutch wetenisse (“witness, testimony”), Old High German gewiznessi (“testimony”), Icelandic vitni (“witness”).

Etymology from Wiktionary, CC BY-SA 3.0