A number that is "close" to (but not equal to) zero may be called an almost zero. In contrast, a number or expression that is equal to zero is said to be identically zero.
The analogous case where is number is "close" to an integer may be called an almost integer.
Given an expression involving known constants, integration in finite terms, computation of limits, etc., determination of if the expression is equal to zero is known as the constant problem.
