optional

optional — adjective

1. available only if someone decides to include it or do it, rather than because a

1.adjectiveB2
Definition

available only if someone decides to include it or do it, rather than because a rule says it is needed

Example

Students can join the museum trip, but the visit is optional.

pattern: be optional

The hotel charged extra for optional breakfast on the second day.

collocation: optional breakfast

Common collocations
  • optional extra
  • optional fee
  • optional course
  • optional trip
  • optional test
Synonyms
  • voluntary

    often used when a person freely chooses to do something

  • elective

    used especially for school subjects or some medical treatment choices

  • extra

    more informal and often used for added features or services

Antonyms
  • compulsory

    states that a rule requires it

  • mandatory

    more formal and common in rules, law, and official instructions

  • required

    the broad everyday opposite

Grammar Patterns

be optional

optional extra

optional course

Usage Note

Often used after be and commonly applied to classes, fees, extras, trips, and parts of a form. Distinguish from possible, which is about what may happen, not about a person's choice.

Common Mistakes

Rain tomorrow is optional.
Going tomorrow is optional.
optional describes a choice someone can make, not an event that may or may not happen.

Word family

Synonym discussion

Sense: adjective/1

Optional means a person may choose it, so it is common for courses, fees, trips, and extra features. Voluntary is close, but it more often focuses on a person's free decision to act, as in voluntary work or a voluntary donation. Elective is narrower and is used especially for school classes or some medical procedures that are chosen rather than required. Compulsory is the clear opposite: it tells you a rule says everyone must do it. Use optional for general choice in systems or plans: The museum trip is optional. Use elective for a school subject: Art is an elective this term.

optional ↗voluntary ↗elective ↗compulsory ↗

Common collocations

Nouns

  • optional extra
  • optional fee
  • optional course
  • optional test

Adverbs

  • entirely optional

Phrases

  • be optional
  • make something optional

Etymology

LatinEnglish

Optional was formed in English from option. That older word goes back to Latin optio, meaning choice, from a verb meaning choose or wish. The modern adjective keeps that idea of having a choice instead of being forced.