Meaning

noun a riblike part of a plant or animal (such as a middle rib of a leaf or a thickened vein of an insect wing)

noun any of the 12 pairs of curved arches of bone extending from the spine to or toward the sternum in humans (and similar bones in most vertebrates)

originFrom pan-Romance (Portuguese Costa, Galician Costa, Spanish Costa, Catalan Costa, Occitan Costa, French Costa, Italian Costa), from Latin costa (“rib; side”).

Etymology from Wiktionary, CC BY-SA 3.0