Definition: "Break wind" is a phrase used to describe the act of expelling intestinal gases from the body through the anus. This is also commonly known as "farting."
In more advanced language, you might encounter phrases like "flatulence" or "passing gas," which are more medical or formal terms for the same action.
While "break wind" specifically refers to the release of gas, in a broader sense, "wind" can also refer to movement of air or the act of breathing (as in "the wind blew").
"Break wind" is a lighthearted way to describe a natural bodily function.