Definition of "Upper" :

noun: a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression

noun: piece of leather or synthetic material that forms the part of a shoe or boot above the sole that encases the foot

"Uppers come in many styles."

noun: the higher of two berths

adjective: higher in place or position

"The upper bunk."

adjective: superior in rank or accomplishment

"The upper half of the class."

adjective: the topmost one of two