ex-

American Heritage® Dictionary of the English Language, Fourth Edition

1. Outside; out of; away from: exodontia.
2. Not; without: excaudate.
3. Former: ex-president.

Century Dictionary and Cyclopedia

1. n. A dialectal variant of ax.
2. n. A dialectal form of ax.
3. A dialectal variant of ask.
4. n. The name of the letter X, x. It is rarely written, the symbol being used instead.
5. A Latin preposition, meaning ‘out,’ ‘out of.’ It is used in English only in certain commercial formulas, as— “20 chests tea ex Sea-King,” where ex means taken out of or delivered from the vessel named;
6. A prefix of Latin, and in some cases of Greek origin, meaning primarily ‘out,’ ‘out of.’ In English words it preserves or reproduces its particular uses in the language of its origin. (See etymology.) Thus, in exclude, exhale, etc., it signifies ‘out,’ ‘out of’; in exscind, ‘off’; in exceed, excel, etc., ‘beyond.’ It is often (especially in the reduced form e-) simply privative, as in exstipulate, eplicate. In some words it is intensive merely, in others it has no particular force. Prefixed to names implying office, ex-signifies that the person has held but is now ‘out of’ that office: as, ex-president, ex-minister, ex-senator.
7. An abbreviation of Exodus.

Wiktionary

1. out of
2. outside
3. former, but still living (almost always used with a hyphen)
4. biology Lacking.

GNU Webster's 1913

1. 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, . 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 é-. 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. The Greek form 'ex becomes ex in English, as in exarch; 'ek becomes ec, as in eccentric.

WordNet 3.0

1. n. a man who was formerly a certain woman's husband
2. adj. out of fashion
3. n. a woman who was formerly a particular man's wife
4. n. the 24th letter of the Roman alphabet