The adjective abdominous means “having a large belly” or “potbellied”.
This word obviously comes from abdomen, which comes straight from Latin, meaning “belly”. The Online Etymology Dictionary supposes that abdomen might come from abdere, Latin for “to conceal”, since it conceals all those guts and whatnot that we’d rather not see.
I thought abdominous was a strange word, because it sounds like a made-up variation of abdominal. But then I found out that the suffix -ous means “possessing” or “full of”. So, literally, the word abdominous means “full of belly”.