英和和英

発音

• (Received Pronunciation) IPA: /ˈɒp.ʃə.nəl/
• (General American) IPA: /ˈɑp.ʃə.nəl/

形容詞

optional (not comparable)

1. Not compulsory; left to personal choice; elective.

   Synonyms: facultative; see also Thesaurus:optional

   Antonyms: compulsory, mandatory, necessary, obligatory; see also Thesaurus:compulsory

   On that beach clothing is entirely optional.

   • 2004, Paula Begoun, The Complete Beauty Bible: The Ultimate Guide to Smart Beauty, Rodale Inc., →ISBN, page 419:

     Do you need to wear eyeliner? As with any makeup step, eyeliner is completely optional. From an artistic perspective, if you are wearing eyeshadow, I almost always recommend wearing eyeliner, unless your eyelids and eyelashes are obscured by the eyebrow area. Eyeliner is a basic part of an eye-makeup design because it shapes and defines the eyes and makes the eyelashes look thicker.

反意語

• non-optional, nonoptional

派生語

関連する語

派生した語

• → Dutch: optioneel
  • → Indonesian: opsional

名詞

optional (plural optionals)

1. Something that is not compulsory, especially part of an academic course.
2. (programming, sometimes capitalized) In various programming languages, a kind of variable that is assigned a specific data type but may or may not hold an actual value.
   • 2015, Richard M Reese, Learning Java Functional Programming, Packt Publishing Ltd, →ISBN, page 147:

     In functional languages, there is a data type called the option type, also called the maybe type. Its purpose is to encapsulate a value, which is returned from a function. […] In Java 8, the Optional class has been added to serve as an option type.

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