<p><strong>Noun:</strong></p><ul><li>A cardinal number, 10 times 3.</li><li>A symbol for this number, as 30 or XXX.</li><li>A set of this many persons or things.</li><li>Printing, Journalism: 30-dash.</li><li>Thirties, the numbers, years, degrees, or the like, from 30 through 39, as in referring to numbered streets, indicating the years of a lifetime or of a century, or referring to degrees of temperature:<ul><li>He works in the East Thirties.</li><li>She must be in her thirties.</li><li>The temperature was in the thirties yesterday.</li></ul></li></ul><p><strong>Adjective:</strong></p><ul><li>Amounting to 30 in number.</li></ul>