Definitions for "Costal"
any of the large paired scales covering much of the carapace of a turtle, excluding the midline and outer rim
the plates on a turtle carapace lying between the median central plates and outer marginal plates
Pertaining to the ribs or the sides of the body; as, costal nerves.
Relating to a costa, or rib.
Of or pertaining to a rib or costa.
fold: The fold along the leading edge of the forewing of a butterfly. It often contains scent scales used to attract other butterflies.