1. A riblike part of a plant or animal (such as a middle rib of a leaf or a thickened vein of an insect wing)
   "The entomologist studied the costa of the butterfly's wing"
    
2. One of the curved bones attached to the spine that protect the chest cavity and organs; usually occurring in 12 pairs in humans
   "The x-ray revealed a hairline fracture on the patient's third costa";
   - rib

Derived forms: costae

Type of: anatomical structure, bodily structure, body structure, bone, complex body part, os[2], structure

Part of: craniate, vertebrate

Encyclopedia: Costa, Michael