patagium

In Latin, patagium referred to a gold edging or border on a woman's tunic, but in English its uses have been primarily scientific. It entered the English language in the early 19th century and was used by entomologists to refer to a process on the back of the foremost segment of an insect. Zoologists borrowed it as a word for the fold of skin of "flying" mammals and reptiles. Then ornithologists took the word to higher heights by the century's end, applying it to the forward part of the wings of birds.