concept
/ˈkɔnsept; `kɑnsɛpt/ n
~ (of sth/that...) idea underlying sth; general notion 观念; 概念
the concept of freedom, meaning 自由的、 意义的概念
He can't grasp the basic concepts of mathematics. 他掌握不了数学的基本概念.
She seemed unfamiliar with the concept that everyone should have an equal opportunity. 看来她不大熟悉机会均等这个概念.