(intransitive, informal) To be knowledgeable in a particular field.

(idiomatic) Alternative form of wouldn't you know it

Used to speculate about a slight possibility.

(of an activity) designed so that participants get to know each other.

Alternative form of know one's own mind

(idiomatic) To be knowledgeable about, and competent at, a particular subject or task.

(informal) I know; I am very familiar with it (some stated fact).

Alternative form of know what is what

(idiomatic) To be experienced or well-informed. / (idiomatic) To be astute, perceptive enough to observe a situation that is not what it seems and recognize its true nature.

Alternative form of know inside and out