Baryonic matter refers to everything in the universe that is composed of protons and neutrons, which are the building blocks of atoms. It includes things like stars, planets, and even living beings. Full definition
But around the same time studies of very distant galaxies, which we see as they were when the Universe was very young, were setting constraints on the amount of baryonic matter in the Universe (New Scientist, Science, 30 April). (newscientist.com)
Some of these x-ray flashes may come from explosions with a relatively large amount of baryonic matter such as protons that produce a «dirty fireball» with higher inertia from their substance, so that the fireball expands slower and is less energetically able to boost photons into the gamma - ray range. (members.nova.org)
Astronomers classify all of this stuff as baryonic matter, and they (and we) know its most fundamental unit as the atom, which itself is composed of even smaller subatomic particles, such as protons, neutrons and electrons. (science.howstuffworks.com)