the.com/optimum

means The best achievable amount or condition under the circumstances — not perfect, just the most anything can be given the constraints.

from Borrowed directly from Latin optimum, meaning 'best,' the neuter form of optimus (superlative of bonus, 'good'). English absorbed it whole in the 19th century as a technical term — first in science and economics, where people needed a word for the best possible result under given limits, not the best imaginable in a world without limits.