What is an Interjection?

An interjection is a word added to a sentence to convey emotion. It is not grammatically related to any other part of the sentence.

What are various examples of interjections?

Common interjections are: Ah, Alas, Dear, Hello, Help, Hey, Hi, Oh, Oops, Ouch, Stop, Uh, Uh-huh, Well, Wow.