When you are getting your Doctorate (and sometimes your Masters) Degree you have to write a thesis (otherwise called “dissertation”). Once the thesis has been accepted by your supervising professor, you have to go before your thesis committee and “defend” your thesis. They will ask you questions about your research and the results you put into your thesis and you have to “defend” the results that you came up with. When the committee cannot find anything wrong with your thesis, then you “pass” your defense and get your degree.
Sounds a bit like Translation.