Akua, atua, makua, matua, and tuan all share the same root word–tua. Tua in Proto-Austronesian meant something akin to some one of an older generation or within a community leadership role. In SE Asia tua became tuan which means lord or noble. In Melanesia (including Western Indonesia) tua became matua which became headman, clan leader, main pole of a house, lead canoe, or parent (depending the language). In Polynesia, tua became both atua and matua. This makes perfect sense since ancestors were deified. Then in Hawaiian atua and matua became akua and makua.