Legal Definition of Senator: A member of the U. S. Senate, or of a state senate. There are two senators elected from each state to the U. S. Senate. States each have their own rules concerning the election of state senators. U.S. senators serve for a term of six years | Learn the Essential Legal Definition of a Senator – Find out everything you need to know about senators in the US, their role and importance, and how they impact the legislative process. As a business owner, it’s crucial to understand this legal term to advocate for policies that benefit your business. Read more now