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: as, the optimal interval for reproduction, the optimal preparation-time, the optimal rate of recurrence, the optimal rhythm, etc.

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.

most desirable possible under a restriction expressed or implied