Is a duet the same as a duplex?

[Karla Simmons]

I had never heard the term “duet” until recently. Is it the same thing as a duplex? If not, what is the difference?

[Steve K.]

Hmm I have a triplex that is titled like this... would it be considered a "Trio"? Would a quad be a "Quartet", a 5plex a "Quintet" and so on? Could buildings with 6 or more units all titled individually be lumped into the "Chamber Ensemble" category until we get up to 30 units which then becomes a "Small Symphony" or an "Orchestra"?