Definition of "atria" []

• A plural of atrium. (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.

• "Now what is happening here -- take a look at this animation, the top chambers of the heart, called the atria, just simply aren't beating effectively."
• "What happens here, Betty, is the top two chambers called the atria just stopped beating normally."
• "It is a condition in which the upper chambers of the heart, called the atria, beat in a rapid and uncoordinated fashion, which can cause blood to pool within the heart."