What is the definition of flatus?

Flatus specifically refers to the gas or air that is expelled from the digestive tract through the anus. This gas is primarily composed of nitrogen, oxygen, carbon dioxide, hydrogen, and sometimes methane, which can be produced during the digestion process by the bacteria in the intestines. The act of passing this gas is a normal physiological process and is commonly referred to as "farting" in everyday language. The other options describe different contexts of gas or air movement but do not align with the specific medical definition of flatus, which is exclusive to gas that is released from the body via the rectum.