What element has the symbol 'O'?

The story behind the answer

The symbol O stands for oxygen. The distractors help: osmium is Os, oganesson is Og, and “olivium” isn’t an element. Oxygen’s atomic number is 8, and it commonly exists as O2, making up about 21% of Earth’s atmosphere—essential for respiration and combustion.

Discovered in the 1770s by Joseph Priestley and Carl Wilhelm Scheele, it was named by Antoine Lavoisier from Greek roots meaning “acid former” (a mistaken idea, but the name stuck). Memory tip: think “O is for O2” and “H2O’s O is oxygen.” You breathe O2, metals rust with it, and it’s the most abundant element in Earth’s crust.