The phrase "senior senator" refers to the senator who has been serving in the position for a longer period of time compared to other senators from the same state. Full definition
So tell me again, what is the point of elevating the incompetent freshman senator over the competent, prepared and multifaceted senior senator in the contest (who won the popular vote)? (voices.washingtonpost.com)
The Democratic senior senator is beating Long by 46 percentage points, up from 39 points last month. (nystateofpolitics.com)
Choo - choo Chuck Schumer, senior senator from New York, seems to have an affinity for Kingston trains. (hudsonvalleyone.com)