The English word is traced back to Tongan "tapu" or the Fijian "tabu". These words usually mean "not allowed", or "forbidden". In its current use in Tonga, the word "tapu" also means "sacred" or "holy", in the sense of being restricted or protected by custom or by law. For example, the main island in the Kingdom of Tonga, where the capital Nuku'alofa is located and most of the population resides, is called "Tongatapu".