Other forms: sentence fragments
A sentence fragment is an incomplete thought or line that lacks the grammar or punctuation that would make it form a whole sentence. In everyday speech, sentence fragments are fine, but you should generally avoid them in formal writing.
There are many ways to write a sentence fragment, starting with lines that are simply incomplete. If you say to your friend, "Because my dog," you've used a sentence fragment. In order to be grammatically correct, sentences have to stand on their own, with clear subjects and verb phrases: "Because my dog ate the turkey, we had pizza for Thanksgiving." A fragment is just a piece of something, from the Latin fragmentum, "a piece broken off."