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X 1 (ĕks)
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n.
A movie rating indicating that admission will not be granted to anyone under the age of 17.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 
x 1 or X (ĕks)
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n. pl. x's or X's also xs or Xs
1. The 24th letter of the modern English alphabet.
2. Any of the speech sounds represented by the letter x.
3. The 24th in a series.
4. Something shaped like the letter X.
5. A mark inscribed to represent the signature of one who is unable to sign one's name.
6. An unknown or unnamed factor, thing, or person.
tr.v. x'd, x'ing, x's or X'd or X'ing or X's
1. To mark or sign with an X.
2. To delete, cancel, or obliterate with a series of X's. Often used with out.
(click for a larger image)
roman numerals, Sundial
Sundials indicate the time of day when a pointer casts a shadow onto a calibrated dial.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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