The official names are "Windows Store Ux" and "Windows Store Apps" and "Start Screen". Metro has stuck with the populace. Microsoft was forced to drop the name due to legal challenges.

>BTW... on an off-topic... Why does it seem like everyone is insisting on referring to "Modern" as "Metro"? The "Metro" name was used prior to official launch of Win8, but it has since been officially renamed as "Modern" if I'm not mistaken.