What do you call it in English when you are presenting your diploma work, in front of juries (which are teachers, Dean and other VIPs ) to get a master degree, during your presentation those juries ask you tricky questions. Translating literally from Ukrainian we, usually, call it "defending the diploma work" because we have to defend ourselves from unexpectable, treacherous questions to make the work to be accepted and proven by juries. Thanks.
In general, it's called an oral defence.
From McGill University:
Prepare to address questions from various perspectives
Most will agree that doctoral candidates who have arrived at the oral defence are actually experts, albeit novice, on the topic of their research. Yet given the format of the public dissertation defence, students are expected to answer questions from those who look at their research from a range of perspectives. Therefore, the defence is a time when they need to think a little bit “outside the box.”
From the University of British Columbia:
The basic structure of the Oral Defence is:
Candidate makes a public presentation of the dissertation (maximum 30 minutes)
Examining Committee members question the Candidate
- Members of the audience are invited to ask questions of the Candidate
- Examining Committee holds an in-camera discussion where it decides on the overall recommendation it will make to Graduate and Postdoctoral Studies (see Evaluation Protocol below)
- Chair conveys the recommendations of the Examining Committee to the Candidate
"Diploma" would be the wrong word to use there because in North America, as far as I'm aware, the word "diploma" refers to the certificate that you receive when you graduate from high school (in order to go to college or university, you first have to finish high school). The longer version of that would be a high school diploma. On the other hand, the certificate that you receive when you graduate from college is called a college degree. The terminology they use in English-speaking countries is completely different from the terminology used in Eastern Europe.
I'm not sure if there is a similar concept in North American countries or Great Britain, but a couple of years ago I did discuss this topic with an American and if I recall correctly, he was referring to the process you're describing in your question as defending your final project.