true rib 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.
Any of the ribs that are attached to the sternum by a costal cartilage, especially any of the seven upper ribs on either side of the thorax in humans.
true rib - Medical Definition
Any of the seven upper pairs of ribs attached to the sternum by costal cartilage.