D defs.my
Entry 1 sense Webster, 1913

optimal

/äp'-təm-əl/ · op·ti·mal · IPA /ˈɑptɪməl/
01 a. Best possible; most desirable; optimum; as, the optimal concentration of a drug.
  1. 1.
    Best possible; most desirable; optimum; as, the optimal concentration of a drug.