Noun
(chemistry) Condition of being saturated with oxygen.
(medicine) Proportion of oxygen-saturated hemoglobin in the blood.
Source: en.wiktionary.orgApple may not be going all out on Oxygen saturation tracking, but with the rest of the core hardware, it is just showing off. Source: Internet
Oxygen saturation In general, hemoglobin can be saturated with oxygen molecules (oxyhemoglobin), or desaturated with oxygen molecules (deoxyhemoglobin). Source: Internet