Hadron, baryon, meson, fermion, boson, lepton, quark. All of these are types of fundamental or nearly-fundamental particles, and there’s a good deal of overlap between them. Keeping them straight is challenging; I have a hard time remembering which is which myself (although I’m not a particle physicist, I have read up on it and know more than most.) So I’m going to explain, for both my edification and yours, what all the -ons (and quarks) are.

Fermions are any particle that obey the Pauli Exclusion Principle, which states that no two fermions can have the same state (which includes position, velocity, etc.) Basically, everything that we typically consider to be ‘matter’, such as protons, neutrons, and electrons, are fermions. One defining property of fermions is that they have non-integer (specifically, a half-integer such as 1/2 or 3/2) spin; spin is a property of fundamental particles and particle-like objects that has nothing to do with actually spinning. A lot of stuff in particle physics is meaningless like that, as we’ll see. So, for example, an electron has spin 1/2, and the composite particles known as delta baryons have spin 3/2. Fermions are named after the famous physicist Enrico Fermi, who first formulated the statistical laws that they obey. Because of the way that spin influences statistics, any particle with an odd number of fermions inside it, such as a proton, which has three fermions inside it, is itself a fermion; any particle with an even number of fermions inside it is not. There are 12 fundamental fermions, and they’re split into 6 leptons and 6 quarks.
Bosons have integer spin and do not obey the Pauli Exclusion Principle, so you can have as many bosons in a given state as you want. Everything is either a fermion or a boson, since its spin is either an integer or not an integer. There are five fundamental bosons: the photon, which carries the electromagnetic force, the Z and W bosons, which carry the weak force, the graviton, which carries gravity, and the Higgs boson, which is not yet confirmed to exist (hence the LHC) but is believed to cause particles to have mass in a way similar to how moving objects through water is difficult.

Quarks are one type of fundamental fermion. The name doesn’t have some deep meaning attached to it; it’s from a poem by James Joyce.  Ignoring antimatter, there are six ‘types’ of quarks: up, down, charm, strange, top, and bottom. The names have nothing to do with directions or anything. Each quark also has a color of either red, green, or blue, which has nothing to do with actual color (see what I mean about names not really meaning much?). One interesting point about quarks is that they (and gluons, which I’ll introduce later) are the only particles that have ‘color’ and so participate in the strong interaction. I’ll cover that in a later post, as it’s worthy of its own discussion. For now, all you need to know is that quarks make up protons (two ups and a down), neutrons (two downs and an up), and essentially everything you think of as ‘matter’ except for leptons. One interesting fact about quarks is that they all have charge either 2/3 or -1/3 times the electron charge, which is odd, as the electron charge is fundamental. However, it is impossible to isolate a quark, for reasons I will explain in that later post I mentioned, so it all works out.

Leptons are the other type of fundamental fermion; the six leptons are the electron, the muon, the tau, and the electron, muon, and tau neutrinos. The muon and the tau are just like the electron, only heavier; they are therefore unstable. Muons decay into muon neutrinos, electrons, and electron antineutrinos, and taus typically decay into a tau neutrino and either an electron and an electron antineutrino or a muon and a muon antineutrino, although there are other decay modes such as a negative pion and a tau neutrino. All tau decay modes do contain a tau neutrino, as they take place via the weak force and so the ‘tau lepton number’, which is the sum of the number of taus and tau neutrinos (antiparticles count for -1), is conserved.

Hadrons are simply particles made up of multiple quarks; they’re split into two groups, baryons and mesons. Baryons are hadrons that contain three quarks; they are therefore also fermions. Protons and neutrons are both baryons, being made of two up quarks and a down and two down quarks and an up, respectively; there are too many baryons for me to list here, but there is a good list on Wikipedia. Mesons are hadrons made up of a quark and an antiquark; they are therefore bosons. Again, there are far too many mesons for me to list here, but Wikipedia has a list of mesons.

A list of all known fundamental particles (sans Higgs boson), from Wikipedia