Definition of "thirteenth" []

• The ordinal number matching the number 13 in a series. (noun)
• One of 13 equal parts. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "“Chechen,” most experts agreed, was a term chosen by Russian colonists after the name of a local village that, ironically, bore the name of thirteenth century Mongol conqueror."
• "Although the image can occasionally be found in thirteenth-century manuscript illumination, the topos did not gain widespread popularity until the fourteenth century."
• "In his study of religious art in thirteenth-century France, Emile Mâle's discussion of Marian iconography includes this observation, "their presentation of the Virgin, a woman old before her time, who weeps over the bleeding face of her Son, became even more purely human, but the figure of the 'Mater dolorosa" which inspired so many masterpieces in the fifteenth century does not belong to the period of our study."