an official document that states that the information on it is true

a birth/marriage/death certificate 出生／结婚／死亡证明

a doctor's/medical certificate 医生／医疗证明

the qualification that you receive when you are successful in an exam

She has a Certificate in Drama Education. 她有戏剧教育资格证书。

to provide an official document as proof that something has happened or been done

She has proposed a series of reforms to the system of reporting and certificating deaths. 她提出了一系列对死亡报告和证明制度的改革。

A welder who has been certificated to work at a certain level must be brought in to do the repairs. 必须请个有一定级别证书的焊工来进行维修。