A physical core (also processing units) or just simply a core is well-partitioned piece of logic capable of independently performing all functions of a central processing unit.

Overview

In its simplest form, such as the case with single-core microprocessors, a core is often synonymous with a central processing unit. In those cases, the entire microprocessor itself is sometimes erroneously referred to as a CPU as well. With the proliferation of commercial multi-core microprocessors since the late 2000s, the term "core" has been used to more concisely describe the individual independent processing units within the microprocessor.