what exactly is "secondary homograph number" ?

[Colin Suggett]

Hi,

I have recently installed FW 8.3 Beta. There is one new feature which is puzzling me. I notice that I have a zero (0) placed beside a lot of my headwords, e.g.:

Eventually, I identified this as coming from "secondary homograph number". 

I think I know what a homograph number is used for, but I'm unclear what a "secondary" homograph number might be, and under what situations this might be useful and/or recommended?

In my example, the headword "duugu" = house, is composed of a root "duu" plus a noun class suffix "-gu". There is only one such noun, but there are three verb entries "duu".

Could someone explain to me what a secondary homograph number is, and why a lot of my headwords have "0" as the result?

Thanks

Colin