Thesis vs Dissertation

 Dissertation vs. Thesis: What's the Difference?

A thesis is a comprehensive paper demonstrating research and critical thinking, typically for a master's degree, while a dissertation is a substantial original research project that contributes new knowledge to a field and is usually required for a doctoral (Ph.D.) degree. Key differences include the academic level, the scope of research (thesis synthesizes existing work vs. dissertation presents original findings), length (dissertations are generally much longer), and the depth of discussion and complexity of the research involved. 

Source: Internet