A slice of tree showing annual rings.
annual ring definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
any of the concentric rings seen in cross sections of the stems of most trees and shrubs: each ring is a layer of wood that normally is a year's growth
annual ring definition by American Heritage Dictionary
nounThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The layer of wood formed in a plant during a single year. Annual rings appear concentric when viewed in cross section.
annual ring - Science Definition
See under growth ring.