The union provides representation for all its members during contract negotiations.

representation 是名词，来自动词 represent（代表）。represent 由前缀 re-（表示"再次"）和 present（呈现、展示）组成，字面意思是"再次呈现"，引申为"代表"。 representation 指"代表行为"或"代表权"，在这里指工会在谈判中代表会员利益的正式权利和职责。