false rib

noun, Anatomy
1.
any of the lower five ribs on either side of the body, which are not directly attached to the sternum.
Origin
1490-1500
British Dictionary definitions for false ribs

false ribs

plural noun
1.
any of the lower five pairs of ribs in man, attached behind to the thoracic vertebrae but in front not attached directly to the breastbone See floating rib
false ribs in Medicine

false rib n.
Any of the five pairs of lower ribs that do not articulate directly with the sternum.