I don't know what they're supposed to be called, but I've looked at more than one source-code and saw it called 'accordian.' Whatever they are called, I think they are a massive eyesore.

This is one of those things where I wish people wouldn't arbitrarily change names. Makes communication more difficult than it needs to be. Seems to be the irritating UI patterns that get refurbed into new names (same shit in a different box). Who would dare rename a button? Buttons are cool. Accordian / slider / moving billboard / whatever is just awful.