Latin word summus comes from Proto-Indo-European *upo (Under, below.), Proto-Indo-European *(t)m̥mo-

Detailed word origin of summus

Dictionary entry	Language	Definition
*upo	Proto-Indo-European (ine-pro)	Under, below.
*(t)m̥mo-	Proto-Indo-European (ine-pro)
*(s)up-(t)m̥mo-	Proto-Indo-European (ine-pro)
summus	Latin (lat)	Highest, greatest, the most high.

Words with the same origin as summus