What is "oxygen-16"

n. (context isotope English) The major stable isotope of oxygen, (nuclide 16 8 O), having eight protons and eight neutrons; it amounts to over 99% of the element in nature

Oxygen-16 (O) is a stable isotope of oxygen, having 8 neutrons and 8 protons in its nucleus. It has a mass of . Oxygen-16 is the most abundant isotope of oxygen, and accounts for 99.762% of oxygen's natural abundance. The relative and absolute abundance of O are high because it is a principal product of stellar evolution and because it is a primordial isotope, meaning it can be made by stars that were initially made exclusively of hydrogen. Most O is synthesized at the end of the helium fusion process in stars; the triple-alpha process creates C, which captures an additional He to make O. The neon-burning process creates additional O.