1 definition by xairbearx

The Juniors and Seniors of a high school they are attending. In other words, eleventh and twelfth graders.

Often they are feared the non-upperclassmen, usually freshmen.
Eleventh Grader: YES! We're eleventh graders! That makes us upperclassmen!!!
Ninth Grader: Uh-ohh.... I'm afraid of getting in the way of an upperclassmen....
by xairbearx June 29, 2009
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