Definition of "concretion" [con•cre•tion]

• The act or process of concreting into a mass; coalescence. (noun)
• The state of having been concreted: a concretion of seminal ideas in her treatise. (noun)
• A solid hard mass. (noun)
• Geology A rounded mass of mineral matter found in sedimentary rock. (noun)
• Pathology A solid mass, usually composed of inorganic material, formed in a cavity or tissue of the body; a calculus. (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.

• "Coquina, of which the fort is built, is a kind of concretion of shell-fragments, often very beautiful."
• "Draw it off by piercing the lower part of the cask, and let it run till the concretion which is formed at the top, and is termed "mother of vinegar," begins to appear."
• "Most likely the structure is a sandy "concretion" that formed after the critter died, says the study."