Is “Plateaux” a Scrabble word?
Yes
PLATEAUX
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Plateaux
/plæˈtoʊ(z)/
noun
1.A largely level expanse of land at a high elevation; tableland.
2.A comparatively stable level in something that varies.
3.An ornamental dish for the table; a tray or salver.