Definition of "thumbtack" [thumbtack]

• A tack with a smooth, rounded head that can be pressed into place with the thumb. (noun)
• To affix with a thumbtack. (verb-transitive)

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.

• "On a thumbtack was a church calendar with a huge picture of Jesus Christ, his hair brown ringlets against a cerulean-blue background, and his eyes heavenward."
• "But there are also more appealing options, such as thumbtack monograms or a dried-bean mosaic of James Brown."
• ""thumbtack" icon shows the last spot they registered online before disappearing a few days ago while traveling waters off the coast of East Africa."