/ ˈɒptɪməm; NAmE ˈɑːp-/ adjective [ only before noun ]
1.
(also op·ti·mal ) the best possible; producing the best possible results :
optimum growth
the optimum use of resources
the optimum conditions for effective learning
2.
the optimum noun [ sing. ] the best possible result, set of conditions, etc.
SYN ideal
••
WORD ORIGIN
late 19th cent.: from Latin , neuter (used as a noun) of optimus best.