"Toyo" in Shinmyo (a god's name) means Toyo no kuni (an area of Buzen Province and Bungo Province combined), deeming the whole Toyo no kuni itself to be a god, that is, Kunitama (a god who manage a province).
神名の豊は豊国（豊前国・豊後国）の意で、豊国自体を神とみたもの、すなわち国魂である。