Difference Between Optimum and Optimal

Main Difference – Optimum vs Optimal

The two words optimum and optimal both have similar meanings and can be used as synonyms. Both mean best, or most favorable. However, there is a slight difference in the usage of these two words. The main difference between optimum and optimal is that optimum is an adjective and a noun whereas optimal is an adjective.

Optimum – Meaning and Usage

The term optimum has been directly borrowed from the Latin noun optimum meaning best. As an adjective, optimum refers to best or most favorable. Oxford Dictionary defines optimum as most conducive to a favorable outcome. Optimum was first known use was in 1879. Given below are some sentences that contain optimum as an adjective.

You have to ferment this mixture for five days to get the optimum taste.

The optimum temperature is between 60°F – 70°F.

This home theater is created for an optimum viewing experience.

Optimum viewing distance can depend on the size of the TV screen.

As explained above optimum can also be used as a noun. The plural form of optimum is optima or optimums. As a noun, optimum refers to the most favorable situation or level of growth, success or reproduction. The following examples will help you to understand this meaning better.

The optimum lies between point B and point E.

The plant can grow in any environment, but the optimum is a dry, humid environment.

The mixture had to be stirred until an optimum is reached.

The solution should be stirred until an optimum is reached.

Optimal – Meaning and Usage

The term optimal is a synonym for optimum. Optimal also means best or most favorable. The main difference between optimum and optimal is that optimum can be used as a both adjective and noun whereas optimal can be only used as an adjective. The noun optimality and the adverb optimally are derivatives of optimal. The first known use of optimal is recorded in 1890. Given below are some sentences that use this adjective.

It is imperative to have a nutritionally balanced diet to achieve optimal health.

You have service it every year for optimal performance.

Her suggestion proved to be the optimal solution for the problem.

These plants can grow up to 12 feet in optimal conditions.

Though both these words, optimum and optimal can be used interchangeably, some grammarians are of the view that optimal should be used as the adjective and optimum should be used as the noun. Bryan A. Garner, in ‘Garner’s Modern American Usage’ states that “It serves the principle of differentiation to distinguish between the two forms,”. However, he also adds that the adjective optimum is edging out optimal in popularity.