Image 1 Caption: Image 1 Besides what it obviously illustrates, the diagram illustrates the usages of the word "fundamental" in physics.

Features:

1. In the blue zone, the elementary particles of the Standard Model of particle physics---which we know is NOT the theory of everything (TOE)---but it is the most fundamental particle physics we have at present. Particle physics is the study of elementary particles and the lowest scale composite particles of which the best known are protons and neutrons.

   To explicate the elementary particles:

   1. Quarks and leptons are fermions. fermions are quantum mechanical particles that obey Fermi-Dirac statics and have half-integer spin: i.e., 1/2, 3/2, 5/2, ... In fact, the Quarks and leptons all have spin 1/2. They also all have rest mass which makes them of matter.
   2. In the Standard Model of particle physics, the 4 fundamental forces (which are NOT the most fundamental forces: see below) are mediated by force-carrier elementary particles: gluons (for the strong nuclear force), W & Z bosons (for the weak nuclear force), photons (for the electromagnetic force), and---by unconfirmed, but widely believed hypothesis---gravitons (for gravity).

2. In the violet zone going downward are main categories of composite particles.

3. In the yellow zone going downward, the forces become MORE united and therefore more fundamental.

   The Standard Model of particle physics unites the electromagnetic force, the strong nuclear force, and the weak nuclear force. Gravitation has NOT yet been united with the other fundamental forces.

   The hypothetical theory of everything (TOE) (for which we have NO established theory, but just a name) is supposed to give that complete unification of the forces among other things. The complete unification would give the singular most fundamental fundamental force.

4. Keywords used in the image:
   atoms (e.g., helium (He)), baryons (e.g., protons, neutrons), composite particles, elementary particles, electroweak theory (a unification of the electromagnetic force and the weak nuclear force), force (the 4 fundamental forces are meant primarily: electromagnetic force gravitation, strong nuclear force, weak nuclear force), force carrier, gluons, grand unified theories (GUTs), graviton, hadrons, leptons (e.g., electrons, positrons, neutrinos), matter, mesons, molecule (e.g., carbon dioxide (CO_2)), nuclei (e.g., the alpha particle (He-4 nucleus)), photons, quantum chromodynamics, quantum electrodynamics, quantum gravity, quarks (e.g., up quarks, down quarks), quark-lepton complementarity, theory of everything (TOE), W & Z bosons.

5. Keywords relevant to the image, but NOT in the image:
   antimatter, boson, dark matter, fermion, Higgs boson (AKA Higgs particle), inflation, massive particles (i.e., particles with rest mass), massless particles (i.e., particles without rest mass: e.g., the photon), particle physics, particles, quantum cosmology, quantum field theory, quantum mechanics, Standard Model of particle physics, string theory, supersymmetry.

   

6. Image 2 Caption: "Standard Model of particle physics has the following elementary particles: the 12 fundamental fermions and 5 fundamental bosons. Brown loops indicate which bosons (red) couple to which fermions (purple and green). Please note that the masses of certain particles are subject to periodic reevaluation by the scientific community. The values currently reflected in this graphic are as of year 2024 and may have been adjusted since. For the latest consensus, please visit the Particle Data Group website." (Somewhat edited.)

7. So there are 17 elementary particles. But the fermions all have distinct antiparticles and the W boson listing gives both charge varieties includes which may add 13 more elementary particles depending on how you think of things.

   Then there is the subject of color charge which triples the number of quarks and gluons and their antiparticles.

   So it's simplest to take the 17 in the table as being the real count of elementary particles.

1. Credit/Permission: © User:Headbomb, 2009 / CC BY-SA 3.0.
   Image link: Wikimedia Commons: File:Particle overview.svg.
   
2. Credit/Permission: User:Cush, 2019 / Public domain.
   Image link: Wikimedia Commons:.