Circle menu
From Halopedia, the Halo wiki
Considered by Halo Wars's Lead Designer, Graeme Devine, is probably the most important menu in the game. So large that the menu itself takes up the whole screen. It is used from, to quote the L.D, "... for everything. To building infantry, to building vehicles, to building buildings and for calling in Leader Powers" The player can navigate through the Circle Menu via the Analog stick, to select whatever they so choose.
Sources
http://forums.halowars.com/forums/1/91352/ShowThread.aspx#91352
