optional

American  

[op-shuh-nl] / ˈɒp ʃə nl /

adjective

1. left to one's choice; not required or mandatory.

   Formal dress is optional.

   Synonyms:

   voluntary, elective, discretional

2. leaving something to choice.

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optional British  

/ ˈɒpʃənəl /

adjective

1. possible but not compulsory; left to personal choice

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Other Word Forms

• nonoptional adjective
• nonoptionally adverb
• optionality noun
• optionally adverb
• unoptional adjective
• unoptionally adverb

Etymology

Origin of optional

First recorded in 1755–65; option + -al ¹

Explanation

If you can choose whether or not to do something, it is optional. Extra credit is always optional; death and taxes are not. When you buy a new car, you can decide which options or choices, you would like. Things like a DVD player mounted in the ceiling are optional, you don't need them for the car to work, and it's up to you if you want to pay more for them. The opposite of optional is mandatory. If you're in high school, going to bed at 8:00 is optional, for your little sister in elementary school, it's mandatory.

Example Sentences

La Mirada Heights is marketed as an independent senior living community designed for older adults who can live on their own while receiving optional support services, according to the facility’s website.

From Los Angeles Times • Mar. 23, 2026

In plans where this is in force, 6.3% took withdrawals, in contrast to 4.9% in plans where the retirement plan is optional.

From MarketWatch • Mar. 12, 2026

Under this system, students can attend optional learning modules before the official start of regular classes in the morning, during midday breaks, or later in the afternoon.

From Science Daily • Mar. 11, 2026

Diners can choose between two omakase menus, with optional nigiri add-ons, late-night alternatives and à la carte selections.

From Salon • Mar. 7, 2026

By the way, all the footnotes on this page have math in them and are therefore strictly optional.

From "An Abundance of Katherines" by John Green