9th Grade (or 1st year at college) - Freshman. 10th Grade (or 2nd year at college) - Sophomore. 11th Grade (or 3rd year at college) - Junior. 12th Grade (or 4th year at college) - Senior.

In the US, for both high schools and colleges, this is how we call each year in class: First year: Freshman Second year: Sophomore Third year: Junior Fourth year: Senior Of course, this system breaks down if you take more than four years to graduate from college. You still can call yourself a senior in the last year, and perhaps freshman in the first year, but usually then you would say "I'm a first year, second year, third year (student), etc."