A quantity which takes on the value zero is said to vanish identically, or sometimes simply to vanish. The term "vanish identically" is preferred when emphasis is needed that a quantity is identically zero (i.e., equal to zero mathematically) instead of simply approximately zero based on outward appearances.
Vanish Identically
See also
Identically Zero, Root, Vanishing, ZeroExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Vanish Identically." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/VanishIdentically.html