'atua' originates from Proto-Polynesian, specifically the reconstructed word '*atua', where the original form denoted a 'spirit' or 'god'.

'atua' continued from Proto-Polynesian '*atua' into many Polynesian languages (for example Māori 'atua', Tahitian 'atua') and was borrowed into English as 'atua' in anthropological and literary contexts.

Initially, it meant 'spirit' or 'god' in Proto-Polynesian, and over time the core meaning has largely remained the same, though in English usage it is typically a loanword used in specific cultural or scholarly contexts.