1、delegate，通常意思是指的被选举或被推出选中出来的代表，来做决策或发表某一团队群体的观点的代表。如，与会代表的代表。
(delegate 做动词时，意味着将权力下放或委托一个人作为代表去执行某件事。)
2、representative，一般指的美国参众两院里众议院里的代表，即众议员。
但是众议员（representative），在美国参众两院中，有时众议员也被叫作delegate。
3、参议院（senate）里的参议员一般只有senator称呼。
4、除此以外，美国国会（The Congress of the United States），众议院里的众议员也用congressman，和congresswoman称呼，参议院里的参议员一般不用做此称呼。
5、为了方便理解我们以弗吉尼亚州议会及其构成为例（以下内容摘自维基百科）：
Commonwealth of Virginia, and the oldest continuous law-making body in the New World (Western Hemisphere), established on July 30, 1619.
The General Assembly is a bicameral body consisting of a lower house（下议院，即众议院）, the Virginia House of Delegates, with 100 members, and an upper house（上议院，即参议院）, the Senate of Virginia, with 40 members.
Combined, the General Assembly consists of 140 elected representatives from an equal number of constituent districts across the commonwealth. The House of Delegates is presided over by the Speaker of the House, while the Senate is presided over by the Lieutenant Governor of Virginia. The House and Senate each elect a clerk and sergeant-at-arms.
The Senate of Virginia's clerk is known as the "Clerk of the Senate" (instead of as the "Secretary of the Senate", the title used by the U.S. Senate).
