The word "core" refers to the central or most important part of something. It can denote the innermost area, the essence, or the foundation upon which something is built. For example, in the context of fruit, the core is the part that contains the seeds. In a more abstract sense, when discussing ideas or values, the "core" represents the fundamental principles that guide someone's beliefs or actions.
The word "core" comes from the Latin word "cor," which means "heart." It has been used in English since the late 14th century to describe the central or essential part of an object or concept.