Yeah I've been kind of struggling with what words to use as well. For now I've been using instances only, never mentioning servers and emphasize the connectedness.
I kind of conflicted. On the one hand, I don't mind too much. This might be slightly mean and non inclusive but this is filtering and gatekeeping and maybe that's okay.
On the other hand I do want more less techy users in to populate the less techy communities. This slows down the joining rate.