Symbols:Numerical Analysis/Tolerance

Tolerance

 * $\pm$

Defines a range in which a number may lie.

$x = a \pm b$ means $a - b \le x \le a + b$.

In the context of engineering, it is known as a tolerance, arising from the idea that any number within $\pm b$ of $a$ is a within a tolerable range of the desired value.

The despicable political term zero tolerance was supposedly coined as a reflection of the above engineering definition.

It of course takes someone with an actual mathematical or engineering background to understand how poisonously unachievable such an aspiration is.

Also see
See:
 * Symbols:Plus or Minus

for other uses of this symbol.