know

For the verb: "to know"

Simple Past:	knew
Past Participle:	known

Concise Oxford English Dictionary © 2008 Oxford University Press:
know/nəʊ/

▶verb (past knew; past part. known)

• 1 be aware of through observation, inquiry, or information.

  ■ have knowledge or information concerning.

  ■ be absolutely sure of something.

• 2 be familiar or friendly with.

  ■ have a good command of (a subject or language).

  ■ have personal experience of.

  ■ (usu. be known as) regard as having a specified characteristic or title.

• 3 archaic have sex with.

– phrases
be in the know informal be aware of something known only to a few people.
God (or goodness or heaven) knows I have no idea.
I know (what) I have a new idea or suggestion.
know something backwards see backwards.
know better than be wise enough to avoid doing something.
know someone by sight recognize someone without knowing their name or being well acquainted with them.
know no bounds have no limits.
know one's own mind be decisive and certain.
know the ropes have experience of the appropriate procedures.
know what's what informal be experienced and competent in a particular area.
not want to know informal refuse to react or take notice.
what do you know (about that)? N. Amer. informal used as an expression of surprise.
you know informal implying something known by the listener.

■ used as a gap-filler in conversation.

– derivatives
knowable adjective,
knower noun.

– origin OE cnāwan (earlier gecnāwan) ‘recognize, identify’, of Gmc origin; rel. to can1 and ken.