Here in Croatia, when students are finishing their 3rd year of undergraduate courses, they usually write a paper called "Završni rad" (eng. Final Work/Project). I'm trying to communicate some things with foreign colleagues and I'm wondering what that would be called in English
Thanks to the Bologna Declaration, the degree system is standardized between European countries, among which Croatia. In this system, the 'undergraduate' degree is called a Bachelor degree. Anyone familiar with European education will not confuse this term with any other degrees, and is likely reminded that you are talking about European education, which may have different requirements for various degrees depending on each country.
As such, the following terms will describe what you mean, without confusing your peers (other than those simply unaware of differences between educational systems). Pick the one that closest resembles what your project actually encompasses - for example, mine was called the Bachelor Final Project because it did not require an extensive report.
- Bachelor thesis
- Bachelor end/final project/paper
- Bachelor dissertation
Note that native BrE or AmE speakers may not agree, but I would like to stress that this may be a cultural difference, not a lingual difference: above phraseology might be quite uncommon because the concept of a bachelor thesis is unfamiliar to academics in the UK or US; I have however seen numerous terms like the above at various continental European universities.
In my experience, in Mathematics, in the U.S., (where "senior year" is typically the last year of an undergraduate degree), things done beyond literal coursework can be called "senior project", "senior thesis", "honors thesis", "senior writing project", or nearly anything similar, with no precise sense from university to university or even from student to student. That is, sometimes "honors thesis" has some actual requirement beyond "senior thesis", but not reliably so...
The term undergraduate dissertation, or Final Year Project Dissertation is also used. The word Thesis is usually reserved for a PHd or research degree.
As already mentioned this is very dependent on local terminology and will vary from country to country, discipline to disciple and institution to institution.
There is no one phrase, since different schools call such projects different things, so I would recommend just trying to a clear translation. The phrase "final project" is frequently used to refer to the final project for a class, so "undergraduate final project" is likely to be more simply understood as what you mean.
From the previous answers, you could see a lot of different names for essentially the same thing. IMO, any suggested name fits, the key here is that you are going to communicate the impact and the results of your work whatever the title you give it.
It is safe to use
I second the comment by @vonbrand, its advisable to give an explanation, but keep it brief unless stated otherwise.
Degree project or Final project is how some other Slavic-speaking places translate their local notion for the thing you write and defend to get a degree. Since it well describes what it is and it's quite a straight translation of the original notion, I would go with it.
Unless, of course, there's an official translation in your transcript. If this is the case, using the official translation is another option.