Core Concepts

[the arrow of egypt]

Hello , Iam really glad to post you for the first time ,I want to ask about this phrase ''CORE CONCEPTS'',what is the meaning exactly?, the word ''CORE''herein is it an adjective?and if it is a noun how could the two nouns be combined that way ? is this phrase means ''fundamental concepts''? in fact the word ''CORE'' embarrassed me because I founded in all dictionaries as noun or verb ,but the meaning I mentioned before is pushing me to look at the word as an adjective ,PLEASE HELP ME WITH DITAILS AND SORRY FOR TOO MUCH TALKING AND I WISH MY ENGLISH IS RIGHT.

[Tdol]

A core concept is a fundamental, central concept that is essential. We can use nouns adjectivally to modify other nouns to indicate the type, etc.