an idea, a belief or an understanding of sth 观念；信念；理解
~ (of sth)
a political system based on the notions of equality and liberty
建立在自由平等观念基础上的政治体系
She had only a vague notion of what might happen.
对于可能发生的事她只有一个模糊的概念。
~ (that…)
I have to reject the notion that greed can be a good thing.
我不能接受那种认为贪欲也可以是件好事的想法。