Definition of "pluralize" []

• To make plural. (verb-transitive)
• Grammar To express in the plural. (verb-transitive)
• To become plural. (verb-intransitive)
• Ecclesiastical To hold more than one position or benefice at one time. (verb-intransitive)

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.

• "(I would also comment that I have NEVER seen anyone use an apostrophe to pluralize denominations of bills.)"
• "For the record, it's also not correct to use apostrophes to pluralize decades."
• "According to the Purdue University Online Writing Lab, there is one case when it's permissable to use an apostrophe to pluralize something."