n.
1.the act of distributing things into classes or categories of the same type
2.a group of people or things arranged by class or category
3.the basic cognitive process of arranging into classes or categories
4.restriction imposed by the government on documents or weapons that are available only to certain authorized people
Idiom of the Day
know (someone or something) by sight
to know the name and recognize the face of someone or something
I know the professor's name but I do not know him by sight.
