What is peter out?

"Peter out" is an idiom that means to gradually diminish or come to an end. It is commonly used to describe something that starts strong but loses momentum over time and eventually fizzles out. The origin of the phrase is uncertain, but it is believed to have been derived from the name "Peter" as a personification of something that begins bravely but loses steam. The phrase is often used in informal conversation and writing and can refer to a range of situations, including relationships, projects, or conversations that lose momentum and eventually stop altogether.