Flatulence is when intestinal gas leaves the anus. This often happens with a sound that can be embarrassing to some people, but in some cultures it is treated like humor. The word flatuence comes from the Latin word flatus, which means blowing or breath, but people today usually call it farting.
In mammals like humans, the gases come from two sources: swallowed air (for example, while eating, talking or drinking) and gases naturally created by bacteria in the body during digestion. Of the gases that come out during flatuence, most of it is nitrogen (which has the chemical formula N2 and makes up between 20% to 90% of all the gases), followed by hydrogen (H), carbon dioxide (CO2), oxygen (O2) and methane (CH4). 
- "Do You Fart a Lot? Here's What Your Flatulence (& Its Smell) Means". Dr. Axe. Retrieved 2018-02-20.
- "Greek Words for Flatulence". SENTENTIAE ANTIQUAE. 2017-06-27. Retrieved 2018-02-20.
- "Flatulence: Causes, Symptoms and Diagnosis". www.healthline.com. Retrieved 2018-02-20.