optional

adjective

op·​tion·​al ˈäp-sh(ə-)nəl 

: involving an option : not compulsory

optionality

ˌäp-shə-ˈna-lə-tē 

noun

optionally adverb

Synonyms of optional

• voluntary
• elective
• discretionary

Examples of optional in a Sentence

Jackets are required at the restaurant, but ties are optional.

Many optional features are available on this car.

Registration is optional, not mandatory.

Recent Examples on the Web

Major health organizations — including the ACC, AHA, Endocrine Society and USPSTF — regard advanced lipid profiles as optional decision-support tools rather than standard screening tests. —Melissa Rudy, FOXNews.com, 8 Dec. 2025

The trailer runs 205/75/R15 tires on 15-in aluminum alloy wheels, and Ecno Evil offers off-road tires as an optional upgrade. —New Atlas, 7 Dec. 2025

Both can save you money in a pinch, but where car insurance is often necessary, a car warranty is optional. —Alora Bopray, USA Today, 5 Dec. 2025

The telescope's adaptive optics system corrects for atmospheric distortions in real time, and optional polarization filters enhance sensitivity to light reflected by dust, making debris disks easier to detect. —Samantha Mathewson, Space.com, 5 Dec. 2025

Word History

First Known Use

1765, in the meaning defined above

Kids Definition

optional

adjective

op·​tion·​al ˈäp-shnəl 

-shən-ᵊl

: left to one's choice : not required

optional equipment on a new car

optionally

-ē

adverb