The importance of the ratio of pulse oxygen saturation to fraction of inspired oxygen (S/F) has been increasingly highlighted. In recent years, multiple clinical studies have confirmed the diagnostic and prognostic value of S/F and its derived parameters in patients with acute respiratory distress syndrome (ARDS). Hence, the 2023 new global definition of ARDS recommended using S/F as both diagnostic criteria and for severity stratification of ARDS. However, there is currently no established Chinese nomenclature for S/F. Considering its inherent meaning, differentiation, and clinical utility, the authors propose the Chinese nomenclature"pulse oxygen index"for S/F. Establishing this nomenclature will facilitate the promotion and application of S/F in academic communication and clinical practice, as well as the new global definition of ARDS.