The third word on 17r has a very clear macron, which is an abbreviation symbol. It means that letters are missing.
The letter that looks like "z" is also a common abbreviation (it is often written exactly like z but it is actually rotated-m and very frequently stands for "em" or "m").
I don't know what the first letter is, it could be b, k, or l (it is not written like s), but the rest is mostly likely -ucrem -ucorem -ucem or something along those lines. What it stands for depends on context, which is hard to determine when the first letter is ambiguous.
The letter that looks like "z" is also a common abbreviation (it is often written exactly like z but it is actually rotated-m and very frequently stands for "em" or "m").
I don't know what the first letter is, it could be b, k, or l (it is not written like s), but the rest is mostly likely -ucrem -ucorem -ucem or something along those lines. What it stands for depends on context, which is hard to determine when the first letter is ambiguous.