What is the maths term for base?

In mathematics, the term "base" can refer to several concepts depending on the context. In number systems, the base (or radix) indicates the number of unique digits used to represent numbers, such as base 10 for decimal or base 2 for binary. In geometry, a base can refer to a side of a geometric figure, such as the bottom side of a triangle or parallelogram from which height is measured. Additionally, in algebra, the base can refer to the number that is raised to a power in exponential expressions.