Dewlap

thumb|right|A mastiff with a dewlap, seen connecting from the neck to the lower jaw. A dewlap is a longitudinal flap of skin or similar flesh that hangs beneath the lower jaw or neck of many vertebrates. More loosely, it can be various similar structures in the neck area, such as those caused by a double chin or the submandibular vocal sac of a frog. More generally, it can be any hanging mass of skin, such as a fold of loose skin on an elderly person's neck, or the wattle of a bird. Dewlaps can be considered as a caruncle, defined as "a small, fleshy excrescence that is a normal part of an animal's anatomy".

==Etymology== The word is first attested in the mid 1300s as dewelappe ("fold of skin that hangs from the throat of oxen and kine"), from lappe ("loose piece", from Old English ), but the first element *dew(e)- is of nebulous origin and meaning; it probably was altered by folk etymology with "dew". Old English had fræt-læppa in the aforementioned sense (and Middle English fresh-lappe). There also seems to be a cognate to Danish dialectal ("flap of skin that sweeps dew from grass, especially on the neck of an ox"), but this might be a parallel independent development. A comparison to dewclaw (also of elusive origin of prefix) has been drawn.