Main definitions of u in English

abbreviation

• Denoting quantum states or wave functions which change sign on inversion through the origin.

• (in units of measurement) micro- (10⁻⁶)

  ‘direct read-out of concentration in ug or mg/l’

nounUs, U's

• 1The twenty-first letter of the alphabet.

  Synonyms

  not in service, unavailable for use, not in use, out of action, unserviceable

  1. 1.1Denoting the next after T in a set of items, categories, etc.

• 2"U"A shape like that of a capital U, especially a cross section.

  in combination ‘U-shaped glaciated valleys’

abbreviation

• 1(in names of sports clubs) United.

  ‘Oxford U’

• 2British Universal (denoting films classified as suitable without restriction).

• 3Uruguay (international vehicle registration).

• 4

  (also u)

  informal You.

  ‘what will u do next?’

• The chemical element uranium.

adjective

• (of language or social behaviour) characteristic of or appropriate to the upper social classes.

  ‘U manners’

  Synonyms

  upper-class, aristocratic, upmarket, Home Counties

noun

• A Burmese title of respect before a man's name, equivalent to Mr.

  ‘U Thien San’