Students and researchers in physics, engineering and other sciences will find this compilation of one letter abbreviations used in mathematics and physics invaluable. All the information included is practical, rarely used results are excluded. Excellent to keep as a handy reference! Selected abbreviations you will find inside this guide: A - Ampere, Area, a Blood type, a Spectral type, Vector potential, Work B - B meson, a Blood type, Boron, Luminance, Magnetic field, a Spectral type C - Carbon, Degrees Celsius, Set of complex numbers, Coulomb, Molar heat capacity (Cp), a Programming language, Specific heat capacity D - Deuterium, Differential operator, Electric displacement E - Electric field, Energy, SI prefix: (exa-), Expected value F - degrees Fahrenheit, Farad, Fluorine, Force, Helmholtz free energy, a Spectral type G - Einstein tensor, SI prefix: (giga-), Gibbs free energy, Gravitational constant, Green's function, Momentum, a Spectral type H - Auxiliary magnetic field, Enthalpy, Hamiltonian, Hankel function, Heaviside step function, Henry, Higgs boson, Homology group, Hubble constant, Hydrogen, Set of Quaternions I - Current, Iodine, Impulse, Luminous intensity, Moment of inertia