Mathematics

• Cauchy–Riemann equations
• Chapman–Kolmogorov equation
• Maurer–Cartan equation
• Pell's equation
• Poisson's equation
• Riccati equation
• sine-Gordon equation
• Verhulst equation

Physics

• Ampère's circuital law
• Bernoulli's equation
• Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy of equations
• Bessel's differential equation
• Boltzmann equation
• Borda-Carnot equation
• Burger's equation
• Darcy-Weisbach equation
• Dirac equation
  • Dirac equation in the algebra of physical space
• Doppler equations
• Drake equation (aka Green Bank equation)
• Earth Similarity Index
• Einstein's field equation
• Euler equations (fluid dynamics)
• Euler's equations (rigid body dynamics)
• Relativistic Euler equations
• Euler-Lagrange equation
• Faraday's law of induction
• Fokker-Planck equation
• Fresnel equations
• Friedmann equations
• Gauss's law for electricity
• Gauss's law for gravity
• Gauss's law for magnetism
• Gibbs-Helmholtz equation
• Gross-Pitaevskii equation
• Hamilton-Jacobi-Bellman equation
• Helmholtz equation
• Karplus equation
• Kepler's equation
• Kepler's laws of planetary motion
• Kirchhoff's diffraction formula
• Klein-Gordon equation
• Korteweg-de Vries equation
• Landau-Lifshitz-Gilbert equation
• Lane-Emden equation
• Langevin equation
• Levy-Mises equations
• Lindblad equation
• Lorentz equation
• Maxwell's equations
• Maxwell's relations
• Newton's laws of motion
• Navier-Stokes equations
• Reynolds-averaged Navier–Stokes equations
• Prandtl-Reuss equations
• Prony equation
• Rankine-Hugoniot equation
• Roothaan equations
• Sackur-Tetrode equation
• Schrödinger equation
• screened Poisson equation
• Schwinger-Dyson equation
• Sellmeier equation
• Stokes-Einstein relation
• Tsiolkovsky rocket equation
• Van der Waals equation
• Vlasov equation
• Wiener equation

Chemistry

• Arrhenius equation
• Butler–Volmer equation
• Eyring equation
• Henderson–Hasselbalch equation
• Michaelis–Menten equation
• Nernst equation
• Schrödinger equation

Biology

• Breeder's equation
• Hardy–Weinberg principle
• Hill equation
• Lotka–Volterra equation
• Michaelis–Menten equation
• Poiseuille equation
• Price equation

Economics

• Black–Scholes equation
• Fisher equation

Technology

• Mansour's equation

Mathematics

• Polynomial equation
  • Linear equation
  • Quadratic equation
  • Cubic equation
  • Biquadratic equation
  • Quartic equation
  • Quintic equation
  • Sextic equation
• Characteristic equation
• Class equation
• Comparametric equation
• Difference equation
  • Matrix difference equation
• Differential equation
  • Matrix differential equation
  • Ordinary differential equation
  • Partial differential equation
  • Total differential equation
• Diophantine equation
• Equation
• Modular equation
• Parametric equation
• Replicator equation

Physics

• Advection equation
• Barotropic vorticity equation
• Continuity equation
• Diffusion equation
• Drag equation
• Equation of motion
• Equation of state
• Equation of time
• Heat equation
• Ideal gas equation
• Ionic equation
• Mass-energy equivalence equation
• Primitive equations
• Relativistic wave equations
• Vorticity equation
• Wave equation

Chemistry

• Chemical equation (aka molecular equation)
• Thermochemical equation

Telecommunications engineering

• Password length equation
• Telegrapher's equations