Definitions of upper:

• noun:   piece of leather that forms the part of a shoe or boot above the sole
• noun:   the higher of two berths
• noun:   a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression
• adjective:   higher in place or position

  Example: "The upper bunk"

• adjective:   superior in rank or accomplishment

  Example: "The upper half of the class"

• adjective:   the topmost one of two