A burp is a belch, or the loud release of trapped air loudly through your mouth. The sound of a burp during a quiet moment makes some people frown and others giggle.
The sound you make when you reflexively let air or gas escape from your mouth is a burp — and to make this noise is to burp. The typical cause of a burp is swallowed air, with some people being able to gulp air and make themselves burp on purpose. Drinking fizzy soda can also make you burp. The word comes from the sound of a burp — it's imitative, and it first appeared in the 1930s.