to see something happen, especially a crime or accident:
Several residents claim to have witnessed the attack.
to experience important events or changes:
Priests have witnessed an increase in religious intolerance.
if a time or place witnesses an event, the event happens during that time or in that place:
Recent years have witnessed the collapse of the steel industry.
if you witness the signing of an official document, you are there when it is signed, and sign it yourself to prove this:
Will you witness my signature?
5 also ..., as witnessed by something
used to introduce an example that proves something you have just mentioned:
Bad economic times can result in political dictatorships. Witness Germany in the 1930s.
to speak publicly about your Christian beliefs