Your tummy is the part of the front of your body below your waist. Tummy is often used by children or by adults talking to children. Your baby's tummy should feel warm, but not hot. = stomach
You can use tummy to refer to the parts inside your body where food is digested. Tummy is often used by children or by adults talking to children. It's easy to get a tummy upset from river water. = stomach. tummies stomach - used especially by or to children