›to see something happen, especially an accident or a crime: The police want to hear from anyone who witnessed the incident.witness an attack/crime
›to sign your name on an official document to prove that an event has happened or that someone is who they say they are: witness an agreement/contract/signatureShe asked a colleague to witness the contract.
›to experience something happening: India witnessed significant jumps in its growth rates as it opened up its economy to international trade.