Gia Long was referred to as Ong Chiang Su[34] (Thai: องเชียงสือRTGS: Ong Chiang Sue[35]) and Chao Anam Kok (Thai: เจ้าอนัมก๊กRTGS: chao anam kok,[36] lit. "lord of Annam") in Siamese royal records; Ong Chiang Su derived from the Vietnamese word Ôngthượng thư ("Sir chief of staff").[34][37] After he crowned the emperor, he was referred as Phrachao Wiatnam Ya Long (Thai: พระเจ้าเวียดนามยาลอง[35][36]).
Literal meaning: "central state". Please note "Trung Quốc" means China or Chinese in present day.
Thụy Khuê 2017, pp. 140–142 Thụy Khuê (2017), Vua Gia Long và người Pháp: khảo sát về ảnh hưởng của người Pháp trong giai đoạn triều Nguyễn. (in Vietnamese), Nhà xuất bản Hồng Đức, ISBN978-6049517655, OCLC1079783921