fourth stomach four-three-two-one rule • fourth ventricle · · · Info · Definitions · Synonyms · Characters · · fourth stomach · · Text Common · · Latin · · Scripts 14 · · Length 3 · · Syllables Definitions · · · (noun) the fourth compartment of the stomach of a ruminant; the one where digestion takes place. Synonyms: abomasum, fourth stomach. · · Noun Definition 1 Synonyms · · · abomasum · · Synonym 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 f latin small letter f U+0066 h latin small letter h U+0068 m latin small letter m U+006D o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074 u latin small letter u U+0075