D defs.my
Entry 1 sense Webster, 1913

Summum bonum

/sŭm'-əm bōn'-əm/ · Sum·mum bo·num · IPA /ˌsʊməm ˈbɑnəm/
01 The supreme or highest good, -- referring to the object of human life.
  1. 1.
    The supreme or highest good, -- referring to the object of human life.(Philos.)