Real Dictionary

stomach
You can refer to the front part of your body below your waist as your stomach.
countable noun: Your stomach is the organ inside your body where food is digested before it moves into the intestines.

stomach in American English
the large, saclike organ of vertebrates into which food passes from the esophagus or gullet for storage while undergoing the early processes of digestion
noun: a saclike enlargement of the alimentary canal, as in humans and certain animals, forming an organ for storing, diluting, and digesting food
transitive verb: to endure or tolerate (someone or something)

stomach in British English
noun: (in vertebrates) the enlarged muscular saclike part of the alimentary canal in which food is stored until it has been partially digested and rendered into chyme