Translation:These are the names of our grandmothers and grandfathers.
Hi Tatka. You can't say These are names of grandmothers. It's correct to say These are names/These are cars/Those are students. But we add "the" at: These are THE names of our grandparents/These are THE names of the cars that I would buy/Those are THE students of my class.
If "žena" is shown as "-a", the accusative of it is shown as "-u", and the unknown form is shown as "-", does that not suggest to you the stripping of the ending, as in žen?
The problem is that we are limited to 5000 characters, so if we have to spell everything out, we just can't provide tips.
With "babička", we would end up with "babičk", and that is weird to say, so there is the "e" insertion. Yeah, if only we had room to explain that.