Empiricism is a theory that states that knowledge comes only or primarily from sensory experience.

Psillos, Stathis; Curd, Martin (2010). The Routledge companion to philosophy of science (London: Routledge)

The Empiricist position is opposed to the Rationalist explanation of epistemology, which states that there are significant ways in which our concepts and knowledge are gained independently of sense experience, or in other words, innately.

(Standford Encyclopaedia of Philosophy)