In the introduction to Shev Shmattsa letter 'מ' he talks about various cases of two things that combine to become one (the guf and the neshama, a mule, someone who is half eved half ben chorin, etc). He says that some things are 'הרכבה מזגית' whereas others are 'הרכבה שכונית'. I'm trying to figure out the translation of these terms.
It seems that הרכבה מזגית means that the two things combine to become one new בריאה, which is not the case by הרכבה שכונית. But I would still like to know the exact translation of the two terms if anyone knows.
edit - I would venture to guess that שכונית comes from the word for neighbor, and it means a combination of two things that only co-exist side by side, but don't actually combine to become one.... but I still don't know what מזגית (or הרכבה ממוזגת) means.