clapper valve clapper rail • clap sill · · · Info · Definitions · Synonyms · Characters · · clapper valve · · Text Common · · Latin · · Scripts 13 · · Length Definitions · · · (noun) a simple valve with a hinge on one side; allows fluid to flow in only one direction. Synonyms: clack valve, clack. · · Noun Definition 1 Synonyms · · · clapper · · Synonym 1 applauder · · Synonym 2 tongue · · Synonym 3 lingua · · Synonym 4 glossa · · Synonym 5 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 l latin small letter l U+006C p latin small letter p U+0070 r latin small letter r U+0072 v latin small letter v U+0076