What is a Thesis?

 
1.  It narrows your subject to a single, central idea that you want readers to gain from your essay.
 
2.  It names the topic and asserts something specific and significant about it.
 
3.  It conveys your reason for writing, your purpose.
 
4.  It often provides a concise preview of how you will arrange your ideas in the essay.
 
The Little Brown Compact Handbook, 4th Edition, University of Phoenix, Jane E. Aaron.