A senator is a person who works in the government. In the United States, senators are elected by voters to represent them in a state or federal senate.
Each state in the US elects two senators who serve six-year terms in Washington, DC, where they pass laws and vote on policies. Other countries have senators as well, either elected or appointed. The word senator has been used in English since around 1200, from the Latin word, senex, or "old man." This is especially appropriate when you know that men have far outnumbered women in the US senate and that the first female senator wasn't elected until 1932.