a person who sees an event, typically a crime or accident, take place

police are appealing for witnesses to the accident

I was witness to one of the most amazing comebacks in sprinting history

evidence; proof

the memorial service was witness to the wide circle of his interests

a line or remnant of an original surface on a workpiece to show how much material has been removed or the shape of the original outline

see (an event, typically a crime or accident) happen

staff who witnessed the murder

have knowledge of (a development) from observation or experience

what we are witnessing is the birth of a new political entity

openly profess one's religious faith

one of the purposes of his coming was to nerve the disciples to witness to Jesus