Does it work for a job title or is it used for academic titles?
Apparently it does not have a well defined meaning, from the bbdb mailing list
So far, the affix field in BBDB 3 does not have a detailed meaning. Its value is a list of strings. So I guess it can stand for all kinds of prefixes, suffixes, academic titles, and what else. But depending on a user's cultural background, the details may vary quite a bit what he or she wants to store in this field and I don't know whether it would make much sense if BBDB tried to establish some universal rules here.
The affix field looks like the following: The affix entry
Dr.is put behind the name (separated by a comma) and before the slash
- before the organisation entry. I guess the reason it was called "affix" is that depending on the culture, entries - for example for academic titles - can be written as prefixes or suffixes.