Translation:the engineer's cat
Yes, you are right. Grammatically it should be قِطَّةُ اَلْمُهَنْدِسِ - however, in spoken Arabic case endings are often not pronounced at all. Even in Modern Standard Arabic (MSA) it's OK to omit case endings in some cases, e.g. at the end of a sentence or "in pausa". There are many rules about this and it's very complicated. In my personal opinion, beginners should (always!) use case endings to make sure they understand the grammar correctly. It doesn't matter that it sounds sometimes weird to natives. A foreigner speaking MSA on the street will sound weird to them anyway :-)
Hello tsuj1g1r1. I absolutely agree that it's quite a hassle. However, just from my personal experience, I believe that it HELPS A LOT to use case endings (especially in the beginning) to fully understand the difference between the grammatical cases (nominative, accusative, genitive), especially when those are not as crucial in your native language. Without case endings, later on it will be more difficult for learners to understand why "the engineers' (plural) cat" is قِطَّةُ المُهَنْدِسِين and not قِطَّةُ المُهَنْدِسُون - hope you understand my pov.
I was confused by the absence of a genitive form, because it seemed normal to me to find a sort of genitive, as in other languages. I knew already, that arabic has genitive cause and tried to find it in the example phrases. Why should the arabic genitive be so much more complicated than genitive in German, Greek etc., that the creators of the course think, its too difficult for us?
Oh, it's not complicated at all. Quite the contrary, it's so simple you missed it even when it was right in front of you! To form the genitive in this particular case, you'd put a short unwritten -i sound at the end of the word مهندس, then you wouldn't pronounce it because it is at the end of the utterance. So you're left with an unpronounced, unwritten sound.
But all hope is not lost. The word that refers to the item possessed also changes form to what is called the "construct" state. In this particular case, the construct of قطةٌ (qi66atun) is simply قطةُ (qi66atu) without the nunation.
You can clearly hear it pronounced that way in the audio prompt, so it turns out it was actually the presence of the genitive form that confused you! :P