upper(redirected from on (one's) uppers)
Also found in: Dictionary, Thesaurus, Medical, Idioms.
1. Geology archaeol denoting the late part or division of a period, system, formation, etc.
2. Maths (of a limit or bound) greater than or equal to one or more numbers or variables
3. Informal any tooth of the upper jaw
4. Slang any of various drugs having a stimulant or euphoric effect
Pertaining to rocks or strata that normally overlie those of earlier formations of the same subdivision of rocks.