core
UK[kɔː]US[kɔːr]
n
The central or most important part of something.
n
The hard central part of a fruit, such as an apple, that contains the seeds.
n
The central part of the Earth or another planet.
adj
Central to the nature or character of something; fundamental.
Etymology
The word 'core' entered English in the 14th century, with its earliest use referring to the central, seed-containing part of fruit. Its ultimate origin is obscure but it is frequently associated with the Latin word cor, meaning 'heart', which itself derives from the Proto-Indo-European root ḱḗr, also meaning 'heart'. This semantic link from the physical, vital organ to the central, essential part of an object or concept is clear and logical. Over time, 'core' expanded from its botanical sense to describe the central part of anything, such as the Earth's core, and later to signify the most fundamental or important element of an abstract idea, system, or group.
Analysis
The word 'core' is a simplex word of uncertain origin, possibly from Old French cuer (heart) or Latin cor (heart). Its functional role is as a complete lexical root.
Examples
The core of the argument was about economic policy.
She cut out the rotten core of the apple.
The course covers the core principles of computer science.