Usually, in birth registers written in Latin twins are called gemini or gemelli (diminutive) if boys, or geminae or gemellae if girls.
But here, the boy twins are uterini. It all means the same thing. This it comes from the word “uterus”.
Be aware, however, that in the description of family trees we often encounter the phrase: “fratres carnali et uterini”. This does not mean twins, but simply full brothers, i.e. those born from the same father and mother, literally: “brothers of flesh and uterus”.
We wish you the best of luck in your research,
Judit and István
P.S. Have you found a Hungarian, Latin or German text and don’t know whether it is worth translating? We can make you an abstract from it! You can learn who wrote it and to whom, when and where it was written, as well as what it’s about, so that you can decide whether or not you want to have it translated. For details, see our webpage: http://historiatranslation.com/abstract/.