# Is there a name for a function which produces the same result when reapplied?

Is there a name for a function which, when applied to its own result, will always return that same result?

e.g. for a function $f(x) = ||x||$

$f(2.5) = 2$

and

$f(f(2.5)) = 2$

• The property is Idempotence. – Mauro ALLEGRANZA Jan 9 '17 at 13:49
• @MauroALLEGRANZA post this as answer for me to mark as correct – goofballLogic Jan 9 '17 at 13:50