u
noun
Definitions
The name of the Latin-script letter U.
A thing in the shape of the letter U
pronoun
Definitions
(abbreviation) you (in text messaging and internet conversations)
Example: Take me with u.
adjective
Definitions
Beneath the surface of the water, or of or pertaining to the region beneath the water surface
Beneath the water line of a vessel
Under water.
Having negative equity; owing more on an asset than its market value
Example: We've been underwater on our mortgage ever since the housing crash.