optional
Americanadjective
-
left to one's choice; not required or mandatory.
Formal dress is optional.
- Synonyms:
- voluntary, elective, discretional
-
leaving something to choice.
adjective
Other Word Forms
Etymology
Origin of optional
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.
Vocabulary lists containing optional
Jim Burke's Academic Vocabulary List
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100 SAT words Beginning with "O"
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Copilot, Microsoft’s flagship AI assistant, is the company’s big bet, and the people building it are on the list of the optional.
From MarketWatch ● Nov. 3, 2026
By 2025, the company had expanded the program to more than forty optional lessons, including short videos and personalized recommendations.
From Salon ● Oct. 25, 2026
It is weighing additional optional exclusions for other AI-related exposures, including agentic AI, according to a Verisk spokeswoman.
From The Wall Street Journal ● Oct. 16, 2026
Dots aren’t even OpenAI’s first cute little things: It launched an optional “pet” for its desktop app last spring.
From Slate ● Oct. 14, 2026
"You chose to write about them for the optional essay question. Would you care to hear what you had to say?"
From "The Catcher in the Rye" by J. D. Salinger
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.