The mass-luminosity (M-L), mass-radius (M-R), and mass-effective temperature (M-T-eff) diagrams for a subset of galactic nearby main-sequence stars with masses and radii accurate to <= 3% and luminosities accurate to <= 30% (268 stars) has led to a putative discovery. Four distinct mass domains have been identified, which we have tentatively associated with low, intermediate, high, and very high mass main-sequence stars, but which nevertheless are clearly separated by three distinct break points at 1.05, 2.4, and 7 M-circle dot within the studied mass range of 0.38-32 M-circle dot. Further, a revised mass-luminosity relation (MLR) is found based on linear fits for each of the mass domains identified. The revised, mass-domain based MLRs, which are classical (L proportional to M-alpha), are shown to be preferable to a single linear, quadratic, or cubic equation representing an alternative MLR. Stellar radius evolution within the main sequence for stars with M > 1 M-circle dot is clearly evident on the M-R diagram, but it is not clear on the M-T-eff diagram based on published temperatures. Effective temperatures can be calculated directly using the well known Stephan-Boltzmann law by employing the accurately known values of M and R with the newly defined MLRs. With the calculated temperatures, stellar temperature evolution within the main sequence for stars with M>1 M-circle dot is clearly visible on the M-T-eff diagram. Our study asserts that it is now possible to compute the effective temperature of a main-sequence star with an accuracy of similar to 6%, as long as its observed radius error is adequately small (<1%) and its observed mass error is reasonably small (<6%).