Re: What's next?
These terms are already gone. Proper terms are "Mainboard" and "Mezzanine" or "Peripheral Board".
P.S. The term "Motherboard and Daughter board" always seemed a bit incestual since the daughter board "plugs in" to the motherboard.
P.P.S. On that basis, daughter board doesn't seem correct either on the basis that the "daughter board" tends to have the "male" connector.
P.P.PS. With gender definitions being redefined, a plug-in board with male connectors could now be legitimately called a "daughter board that identifies male".