pneumatic caisson pneumatically • pneumatic drill · · · Info · Definitions · Synonyms · Characters · · pneumatic caisson · · Text Common · · Latin · · Scripts 17 · · Length 6 · · Syllables Definitions · · · (noun) large watertight chamber used for construction under water. Synonyms: caisson, pneumatic caisson, cofferdam. · · Noun Definition 1 Synonyms · · · caisson · · Synonym 1 cofferdam · · Synonym 2 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 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E o latin small letter o U+006F p latin small letter p U+0070 s latin small letter s U+0073 t latin small letter t U+0074 u latin small letter u U+0075