from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A movie rating indicating that admission will not be granted to anyone under the age of 17.
- The symbol for reactance.
- The symbol for the Roman numeral 10.
- abbr. Christ (Greek &KHgr;&rgr;&igr;&sgr;&tgr;&ogr;&sfgr;, Christos)
- abbr. Christian
- abbr. experimental
- abbr. extra
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The twenty-fourth letter of the basic modern Latin alphabet.
- n. The number 10.
- n. A symbol of the IPA, representing a voiceless uvular fricative.
- n. strike
- n. A hazard indicator, sometimes incorporated into standard labelling and signage systems
- n. An unknown quantity or unknown value.
- n. The twenty-fourth letter of the English alphabet, called ex and written in the Latin script.
- n. Any mark that looks like that letter, such as such a mark made by a person who cannot read or write, in lieu of a signature.
- n. The spot behind the goal.
- n. Ecstasy, a particular street drug.
- adj. Suitable only for those aged 16 or (later) 18 years and over.
- adj. Obscene.
- abbr. Christ
- abbr. cross, crossing
- n. One of the tristimulus values which, with Y and Z, defines coordinates in a three-dimensional color space. Pronounced big X or cap X.
Possibly from skull and crossbones (Wiktionary)
Presumably by abbreviation of the pronunciation of ecstasy. (Wiktionary)
From Christ by abbreviation, from Ancient Greek Χ (Ch, "(letter chi)"), from Χριστός (Christós, "Christ"). (Wiktionary)
As defined in CIE 1931 color space. (Wiktionary)