Constant is the concept, the property of the variable.
final is the java keyword to declare a constant variable.
As other people pointed out, from a semantic/linguistic point of view the expression constant variable is an oxymoron and, as such, we could argue about its correctness.
Quoting the specification, anyway, we can read
A variable of primitive type […], that is final and initialized with a compile-time constant expression (ยง15.28), is called a constant variable.
I suppose, hence, that we can accept (and consider correct) this binomial for our purpose.