1. A variable quantity or value; specific uses include physics, a quantity that is used in a relationship involving several quantities and is held fixed, but in general it may be allowed to have different values.
2. In computer programming, data that can take different values at the execution time of a function, procedure, macro-instruction, or subroutine.

Only a specialist in mathematics or computing might know precisely what it means.

When the word does have a discernible meaning, it is usurping the place of a far simpler and more straightforward term; such as, boundaries, limits, or guidelines.