Approximation

noun

1. The act, process, or result of approximating.
2. An inexact result adequate for a given purpose.
3. The act of approximating; a drawing, moving, or advancing near in space, position, degree, or relation; approach; proximity.
4. In mathematics and physical: A continual approach to a true result; the process by which the value of a quantity is calculated with continually increasing exactness without ever being actually ascertained
5. A result so obtained; a result which is not rigorously exact, but is so near the truth as to be sufficient for a given purpose.