the best or most favorable point, degree, amount, etc., as of temperature, light, and moisture for the growth or reproduction of an organism. the greatest degree or best result obtained or obtainable under specific conditions.

What does it mean for something to be optimal?

Optimal and optimum both mean “best possible” or “most favorable.” Optimal is used solely as an adjective, as in “optimal method of completion, while optimum functions as both a noun, as in something “being at its optimum,” and an adjective, “optimum method,” although this is less common.

What is an example of optimal?

The definition of optimal is the most favorable. An example of optimal used as an adjective is in the phrase "optimal score," which means the highest score someone can get on a game. Most favorable or desirable; best; optimum. The best, most favourable or desirable, especially under some restriction.