thirteen

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The cardinal number that is equal to the sum of 12 + 1.
• noun The 13th in a set or sequence.
• noun Something having 13 parts, units, or members.

from The Century Dictionary.

• Being three more than ten; consisting of one more than twelve: a cardinal numeral.
• noun The number which consists of the sum of twelve and one, or of ten and three.
• noun A symbol representing thirteen units, as 13, XIII, or xiii.
• noun A silver shilling worth 13 pence, current in Ireland during the early part of the nineteenth century.

from the GNU version of the Collaborative International Dictionary of English.

• adjective One more than twelve; ten and three.
• noun The number greater by one than twelve; the sum of ten and three; thirteen units or objects.
• noun A symbol representing thirteen units, as 13 or xiii.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The cardinal number occurring after twelve and before fourteen, represented in Roman numerals as XIII and in Arabic numerals as 13.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective being one more than twelve
• noun the cardinal number that is the sum of twelve and one