optional

名词 n. 形容词 adj.
中文释义
英 /ˈɒp.ʃə.nəl/    美 /ˈɑp.ʃə.nəl/

英文释义

名词 n.
  1. Something that is not compulsory, especially part of an academic course.
  2. In various programming languages, a kind of variable that is assigned a specific data type but may or may not hold an actual value. capitalized,sometimes
    — 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.
形容词 adj.
  1. Not compulsory; left to personal choice; elective. not-comparable
    — On that beach clothing is entirely optional.

词形变化

optionals plural

词汇关系

反义词
non-optional nonoptional compulsory mandatory obligate obligatory required requisite

词源

词源 1
Etymology tree
English option
Proto-Indo-European *h₂el-der.?
Proto-Italic *-ālis
Latin -ālisbor.
Old French -albor.
▲
Latin -ālis
Old French -elbor.
▲
Latin -ālisbor.
Middle English -al
English -al
English optional
From option + -al.
词源 2
Etymology tree
English option
Proto-Indo-European *h₂el-der.?
Proto-Italic *-ālis
Latin -ālisbor.
Old French -albor.
▲
Latin -ālis
Old French -elbor.
▲
Latin -ālisbor.
Middle English -al
English -al
English optional
From option + -al.
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