optimal

Most favorable or desirable; optimum.

Best; most favorable: specifically, in experimental psychology, referring to the frequency or duration of stimuli, to the length of intervals between experiments, etc., so timed as to allow of most accurate reproduction or apprehension, or of most adequate attentive preparation.

Of or pertaining to the optimum, as of temperature, moisture, etc. See optimum.

Best possible; most desirable; optimum.

The best, most favourable or desirable, especially under some restriction.