a person who gives evidence in a court 目击者；（法庭上的）证人◆a defence/prosecution witness 被告／原告证人◆She appeared as (a) witness for the defence/prosecution. 她出庭为被告／原告作证。⨁to act as / appear as / be called as a witness 作证；出庭／被传作证
a person who is present when an official document is signed and who also signs it to prove that they saw this happen （官方文件签署时的）连署人，见证人◆She signed and dated the document in front of a witness. 她当着见证人的面在文件上签字并写上日期。