What is navigating backwards through the Alt-Tab UI called?

In Windows, you can use Alt+tab to navigate through windows in "Most recently used" order (MRU order). Subsequent tab keypresses will continue to move you through the MRU ordering, until alt is released.

If you instead press Alt+shift+tab, the UI will navigate backwards through that list. However, what's that action called? The action here of navigating backwards through the MRU list.

It's not the "next most recently used window", but it's also not the "previously most recently used window", nor is it the "last most recently used window" - those are all the same thing, the window you just came from.

My use case here: We're using nextTab to select the next tab (in-order), and prevTab to get at the previous in-order tab, but suddenly those names don't apply so well when we're talking about MRU navigation between tabs. nextMRUTab and prevMRUTab are the semantically same thing