What vibrations are called harmonic?

Harmonic vibrations are vibrations in which physical quantities (coordinate, speed, acceleration) change according to the harmonic law: x (t) = A * sin (ωt + φ) or x (t) = A * cos (ωt + φ) , where x is the deviation from the equilibrium position (the origin of the coordinate system), A is the amplitude value (maximum value of x, velocity, acceleration), ω is the cyclic frequency, φ is the phase of oscillations.