baryon oscillation is basically sound waves in the early Universe.
One of those observations is BOSS: the baryon Oscillation Spectroscopic Survey.
Any of a family of subatomic particles composed of three quarks or three antiquarks. They are generally more massive than mesons, and interact with each other via the strong force. Baryons form a subclass of hadrons and are subdivided into nucleons and hyperons. Protons and neutrons are baryons. See Table at subatomic particle.