know 
(nō)
(nō)v. knew (n, ny), known (nōn), know·ing, knows
v.tr.
1. To perceive directly; grasp in the mind with clarity or certainty.
2. To regard as true beyond doubt: I know she won't fail.
3. To have a practical understanding of, as through experience; be skilled in: knows how to cook.
4. To have fixed in the mind: knows her Latin verbs.
5. To have experience of: "a black stubble that had known no razor" (William Faulkner).
6.
a. To perceive as familiar; recognize: I know that face.
b. To be acquainted with: He doesn't know his neighbors.
7. To be able to distinguish; recognize as distinct: knows right from wrong.
8. To discern the character or nature of: knew him for a liar.
9. Archaic To have sexual intercourse with.
v.intr.
Idioms: 1. To possess knowledge, understanding, or information.
2. To be cognizant or aware.
know (someone) in the biblical sense
To have sexual relations with (someone).
in the know Informal
Possessing special or secret information.
you know Informal
Used parenthetically in conversation, as to fill pauses or educe the listener's agreement or sympathy: Please try to be, you know, a little quieter. How were we supposed to make camp in a storm like that, you know?
[Middle English knouen, from Old English cnāwan; see gnō- in the Appendix of Indo-European roots.]
knowa·ble adj.
knower n.