(追記) (追記ここまで)
Independent Variable
A variable in an equation that may have its value freely chosen without considering values of any other variable. For equations such as y = 3x – 2, the independent variable is x. The variable y is not independent since it depends on the number chosen for x.
Formally, an independent variable is a variable which can be assigned any permissible value without any restriction imposed by any other variable.
See also