thereallieutenantcommanderdata:

The convention of using the symbiote’s name as a kind of surname for a joined Trill is really odd to me.  At least, as it translates into our culture, perhaps their own culture has different conventions

But the thing is, “Jadzia” and “Dax” are different people.  When you address her as “Lieutenant Dax”, you’re effectively addressing the symbiote while when you address her as “Jadzia”, you’re addressing the host. So, it’s not the same as, say, the distinction between saying “Captain Sisko” and “Benjamin”, because “Sisko” and “Benjamin” refer to the same person

So, it seems to me that it would make more sense to simply treat “Jadzia Dax” as a single name (”Jadzia-Dax”), and then using either “Jadzia” or “Dax” by itself would be reserved for times when one is referring solely to the symbiote or solely to the host

And there’s certainly precedent for treating aliens as having single names.  Worf’s full name is “Worf Son of Mogh”, but “Son of Mogh” isn’t treated as a surname.  He’s “Lt Worf” not “Lt Son-of-Mogh” or “Lt Moghson”.  And Spock was only ever Spock, and there’s no official canon for his surname (there’s a semi-canonical name but I can’t remember it)

i can sort of see how the connection of people who shared a symbiote is comparable to a family, as another line of descent comparable to patrilineal surnames. it makes sense that in trill culture, your symbiote becomes more important and that it sort of replaces any other kind of family tree you had before. it fits in a lot with how trills pre and post joining are considered different people. at least, this was the easiest way that i could make sense of this question when i watched it. i wonder if joined trills are technically disowned by their family too, if their culture sees the joined trill as a new person (or maybe trills don’t ever have last names? it’s been a while) (i can also see joined trills being disallowed from receiving inheritances, so that you can’t profit from just having had previous hosts. there is also that law about meeting people who knew a past host, i guess they’d have a lot of laws to avoid joined trills abusing their status for money or power or connections)