...not luan. I knew yall would want to know. If you pronounce it "luan" at cocktail parties, however, you are fine. Merriam Webster's online dictionary gives that as the first pronunciation, in fact.
Same source reveals that it is from "lawaan". Which is a Tagalog word. For "lauan", I'm guessing.
While we're reveling in trivia, "lauan" plywood is actually made from Shorea trees, just like meranti!
I can't recall this bit: either the good stuff must get thrown in the meranti (read, "expensive") bin and the garbage into the "lauan" bin. Or, perhaps lauan comes from a different species of the Shorea genus. (There are a whole bunch of them.)
Anyway, the next step in Home Depot-style plywood evolution will surely be compressed sawdust with one coat of lauan paint on the "A" side.