Meteorites contain tiny (0.002-10 mum) mineral grains which formed around stars or in stellar explosions,. These grains have unusual isotope compositions that reflect those of the stars in which they formed. Stardust composed of nanodiamonds, silicon carbide (SiC), silicon nitride (Si3N4) or graphite are believed to derive from a range of stellar types,, whereas the oxygen-rich grains found to date are thought to originate only in red giants and asymptotic giant branch stars. We report here an oxide grain that is extremely rich in the isotope oxygen-16 (16O), in an acid-resistant residue of the Tieschitz meteorite. This grain, T84, probably derives from the ejecta of a type II supernova and is the first reported oxide grain derived from such a source, despite 16O being the third most abundant isotope ejected by supernovae (after hydrogen and helium).