It's actually "Hear, hear", and yes, it is an exclamation. https://en.wikipedia.org/wiki/Hear,_hear "Hear, hear is an expression used as a short, repeated form of hear him. It represents a listener's agreement with the point being made by a speaker. It was originally an imperative for directing attention to speakers, and has since been used, according to the Oxford English Dictionary, as "the regular form of cheering in the House of Commons"" In summary: It's something you say when there is a public meeting with a speaker, and you agree with what the speaker at the meeting has just said. As you can tell, that's a really specific situation, so it's not used that much.