The Collaborative International Dictionary of English v.0.48:

ex \ex\ ([e^]ks), n.
   The letter x.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

ex \ex\ ([e^]ks), prep. (Finance)
   Without (some right); not including the right to have; as, a
   stock selling ex dividend (a stock for which the right to a
   dividend has expired the previous day); ex interest; ex
   rights.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Ex- \Ex-\ ([e^]ks).
   A prefix from the latin preposition, ex, akin to Gr. 'ex or
   'ek signifying out of, out, proceeding from. Hence, in
   composition, it signifies out of, as, in exhale, exclude;
   off, from, or out, as in exscind; beyond, as, in excess,
   exceed, excel; and sometimes has a privative sense of
   without, as in exalbuminous, exsanguinous. In some words, it
   intensifies the meaning; in others, it has little affect on
   the signification. It becomes ef- before f, as in effuse. The
   form e- occurs instead of ex- before b, d, g, l, m, n, r, and
   v, as in ebullient, emanate, enormous, etc. In words from the
   French it often appears as es-, sometimes as s- or ['e]-; as,
   escape, scape, ['e]lite. Ex-, prefixed to names implying
   office, station, condition, denotes that the person formerly
   held the office, or is out of the office or condition now;
   as, ex-president, ex-governor, ex-mayor, ex-wife, ex-convict.
   The Greek form 'ex becomes ex in English, as in exarch; 'ek
   becomes ec, as in eccentric.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

ex \ex\ ([e^]ks), n. [contraction]
   An ex-wife or ex-husband; a former spouse; -- used usually
   with a possessive; as, she invited her ex to her second
   wedding; her ex; his ex; John's ex. [informal]
   [PJC]

WordNet (r) 3.0 (2006):

ex
    adj 1: out of fashion; "a suit of rather antique appearance";
           "demode (or outmoded) attire"; "outmoded ideas" [syn:
           antique, demode, ex, old-fashioned, old-hat(p),
           outmoded, passe, passee]
    n 1: a man who was formerly a certain woman's husband [syn: ex-
         husband, ex]
    2: a woman who was formerly a particular man's wife; "all his
       exes live in Texas" [syn: ex-wife, ex]
    3: the 24th letter of the Roman alphabet [syn: X, x, ex]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "ex":
   aside from, bar, barring, beside, besides, except, except for,
   excepting, excluding, exclusive of, from, leaving out, let alone,
   omitting, out, out of, outside of, precluding, save,
   save and except, saving, than, unless, without