The pendulous skin under the neck of an ox, or a similar feature on any other animal.
1901 – 1902, Arthur Conan Doyle, The Hound of the Baskervilles
Fire burst from its open mouth, its eyes glowed with a smouldering glare, its muzzle and hackles and dewlap were outlined in flickering flame.
The sagging flesh on the throat of an elderly human.