signum function

Noun

 * 1)  The function that determines the sign of a real number, yielding -1 if negative, +1 if positive, or otherwise zero.

Usage notes
The equivalent term sign function may be avoided in speech because of possible confusion with sine.

Translations

 * German: Signumfunktion
 * Hungarian: előjelfüggvény
 * Russian: зна́ковая фу́нкция
 * Turkish: işaret fonksiyonu