The word fragment means a piece of something that is broken, such as a fragment of glass from a broken mirror.
A sentence fragment is a broken piece of sentence or a part of a sentence.
It is important to use complete sentences when you write; don’t use fragments.
A common writing error that produces a sentence fragment is when we use a subordinate clause as a sentence. Remember, a subordinate clause must always be attached to an independent clause to make a complex sentence. When you write a subordinate clause all by itself, it creates a sentence fragment.
Look at these subordinate clauses:
Because it’s raining.
While I do the laundry.
When you finish your homework.
Each of these is a subordinate clause because each one begins with a subordinate clause word. But each is also a sentence fragment because there is no independent clause to finish the sentence.
In order to fix these sentence fragments, we must add an independent clause, like this:
Because it’s raining, the porch furniture is all wet. OR The porch furniture is all wet because it’s raining.
While I do the laundry, you can walk the dog. OR You can walk the dog while I do the laundry.
When you finish your homework, you can watch the movie. OR You can watch the movie when you finish your homework.
A subordinate clause alone is a fragment. Always attach an independent clause to a subordinate clause to make a complete sentence.