noun

1. The name of the Latin-script letter U.

2. A thing in the shape of the letter U

pronoun

1. (abbreviation) you (in text messaging and internet conversations)

   “Take me with u.”

adjective

1. Beneath the surface of the water, or of or pertaining to the region beneath the water surface

2. Beneath the water line of a vessel

3. Under water.

Synonyms: subaquatic, subaqueous, submarine, upside down