From Longman Dictionary of Contemporary Englishtumtum /tʌm/ noun [countable] British English informal stomach SYN tummy I’ve lost another two inches from my tum.
Examples from the Corpus
tum• This lovely pin stripe looks a lot sexier on our slinky slicker than stretched across some tycoon's big tum.• Santa's first shock came from the tape measure - the Claus tum measured a bloated 47 inches.• Another ¾ from my tum and whilst my thighs and knees remain the same I've lost ¼ inch off each arm.Origin tum (1800-1900) tummy 