Speaking for myself, I would say that mathematics is axiomatic theory.
That is, it defines arbitrary axioms, and builds theories based on those axioms.
This is what sets math apart from all other sciences at a lonely distance.
All other sciences are based on empirical observations and merely use math as a tool to describe them.
For instance, we have the axioms of rings of integers and the axioms of fields of real numbers. The theories based on integers respectively real numbers follow from them. Similarly we have axioms of set theory, and the theories on set theory follow from them.
According to
Mathematics on wikipedia there is no generally accepted definition. However, it does mention that:
Since the pioneering work of Giuseppe Peano (1858–1932), David Hilbert (1862–1943), and others on axiomatic systems in the late 19th century, it has become customary to view mathematical research as establishing truth by rigorous deduction from appropriately chosen axioms and definitions.