%0 Journal Article %T The Meaning of Mass %J International Journal of Theoretical and Mathematical Physics %@ 2167-6852 %D 2012 %I %R 10.5923/j.ijtmp.20120204.03 %X Electron, proton and neutron are described in terms of energy densities on least-action paths to show that their charges, magnetic moments and masses are manifestations of quantized geodesics. According to this geometric understanding of matter, the mass of a particle depends on how much the particle-associated curved path projects onto the straight paths of the universal surrounding energy density. The reference density of free space is embodied by the most elementary actions, the photons in propagation on their least-time paths. The vacuum density with random distribution of photon phases displays no electromagnetic field, yet the propagation of its force carriers will level off density differences. This manifests itself as gravitation. Transformations from one particle to another, for example oscillations, are described according to NoetherĄ¯s theorem as changes from one action to another. This physical portrayal of quantized nature, where every entity comprises multiples of the most elementary action, parallels the atomistic tenet. %K Baryon %K Geodesic %K Gravitation %K Lepton %K Meson %K Quark %K Symmetry %K The Principle of Least Action %U http://article.sapub.org/10.5923.j.ijtmp.20120204.03.html