Illustration of patagium
- P patagium 1
patagium
noun
pa·ta·gi·um pə-ˈtā-jē-əm 
plural patagia pə-ˈtā-jē-ə
1
: the fold of skin connecting the forelimbs and hind limbs of some tetrapods (such as flying squirrels)
2
: the fold of skin in front of the main segments of a bird's wing
Did you know?
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.
Example Sentences
Recent Examples on the Web Flying squirrels don’t have their own means of propulsion, like a bird or bat, but glide using a furry membrane called the patagium that connects at their wrists down to their ankles. 
National Geographic, 21 Aug. 2020 The presence of a patagium—the skin linking the upper arm to the lower—helps generate lift and is an adaptation generally thought to be necessary for gliding or flight. National Geographic, 28 Feb. 2017
National Geographic, 21 Aug. 2020 The presence of a patagium—the skin linking the upper arm to the lower—helps generate lift and is an adaptation generally thought to be necessary for gliding or flight. National Geographic, 28 Feb. 2017 Word History
Etymology
New Latin, from Latin, gold edging on a tunic
First Known Use
1857, in the meaning defined at sense 1