They have nearly the same meaning. When I googled these two words, I didn't get useful information (all the results are about thesis or papers, not the words themselves).
Can anyone help?
A "thesis" or "thesis paper" is considered more important than just a "paper." In American colleges, a thesis must be submitted and approved to obtain a master's degree. It is a research paper that requires a substantial amount of work -- it could be dozens or hundreds of pages long. The topic is often the specialization or concentration the student chose to pursue, and it often requires the approval of one or more professors before the student can graduate. Sometimes a thesis is rejected, and the student must spend another semester improving it before submitting again. In fine arts, a thesis can refer to the best work from a student's portfolio, such as a set of oil paintings or a collection of poetry. Ultimately, the thesis should represent what the student has learned and achieved while pursuing their degree.