cottonmouth

[ kot-n-mouth ]
/ ˈkɒt nˌmaʊθ /

noun, plural cot·ton·mouths [kot-n-mouths, -mouth z] /ˈkɒt nˌmaʊθs, -ˌmaʊðz/.

a venomous snake, Agkistrodon (Ancistrodon) piscivorus, of swamps in southeastern U.S., that grows to about 4 feet (1.2 meters).
Also called water moccasin.

Origin of cottonmouth

1825–35, Americanism; cotton + mouth, so called from the whiteness of its lips and mouth

British Dictionary definitions for cotton mouth

cottonmouth
/ (ˈkɒtənˌmaʊθ) /

noun

another name for the water moccasin