Localization (commutative algebra)
In commutative algebra and algebraic geometry, localization is a formal way to introduce the "denominators" to a given ring or module. That is, it introduces a new ring/module out of an existing ring/module R, so that it consists of fractions m s , {\displaystyle {\frac {m}{s}},} such that the denominator s belongs to a given subset S of R. If S is the set of the non-zero elements of an integral domain, then the localization is the field of fractions: this case generalizes the construction of the field Q {\displaystyle \mathbb {Q} } of rational numbers from the ring Z {\displaystyle \mathbb {Z} } of integers.
Source: Wikipedia — Localization (commutative algebra) (CC BY-SA 4.0)