Often a variable is only assigned to once and is used as an (immutable) definition.

通常对变量的赋值只有一次，并被当作不变的对象。

youdao

Scala allows you to decide whether a variable is immutable (read-only) or not (read-write) when you declare it.

当你声明一个变量的时候，Scala允许你来决定它是不变的(只读的)还是可变的(可读写的)。

youdao

An immutable "variable" is declared with the keyword val (think value object).

一个不变的“变量”可以用val关键字来声明(想象一个值对象)。

youdao