What is the (etymological or other) origin of those ottoman like nürettin, şerafettin etc (please throw others into the mix if they spring to mind)?
are they ottoman or arabic or persian, originally?
i just came across a certain Shigabutdin, the spelling of which made me think the last part may come from "din", "religion".


sharaf ud din is the nobility of religion.
Same root as the sharif of Makkah or Omar Sharif.

Shihab is a falling star. It is also used for the torch that lights the path while traveliing at night. So torch of the religion.
There is also Shamsuddin= Sun of the religion.
Nasiriddin= supporter of the religion.
Alamuddin= Flag of the religion.
and there are many others. Then there is this:
Qamaruddin= moon of the religion. This term is however used, in the levant, for sheets of dried apricot that are sold in Ramadan, therefore the moon connection. People use them to make Apricot juice which they drink as they break their fast.
The history of those terms is that they were used as honorific titles to be given to leaders or judges or scholars. They were in addition to their actual names. for examples Saladdin was called by the tile Nasireddin. However, more recently, those titles became proper names.
I hope this helps and take care all.