op ‧ ti ‧ mum /ˈɒptəməm, ˈɒptɪməm $ ˈɑːp-/ BrE AmE adjective [only before noun]
[ Date: 1800-1900 ; Language: Latin ; Origin: 'best' ]
the best or most suitable for a particular purpose or in a particular situation:
optimum conditions for growth
This design makes the optimum use of the available space.
—optimum noun [singular]