Costal \Cos"tal\ (k?s"tal), a. [Cf. F. costal. See Costa.]

1. (Anat.) Pertaining to the ribs or the sides of the body; as, costal nerves.

2. (Bot. & Zo["o]l.) Relating to a costa, or rib.

Costal cartilage. See Cartilage, and Illust. of Thorax.

Source: Webster's Revised Unabridged Dictionary (1913)