Caption: 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 physics theory we have at present.

   In the standard model of particle physics, the 4 fundamental forces (which are NOT 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, hypothetically, gravitons (for gravity gravity).

2. In the violet zone going downward, particles become less fundamental and more describable as 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 single 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.