The Q factor, or quality factor, also pertains to oscillating systems, although it has a different definition in that context. It can be defined in many ways, one of which relates to the response of a driven resonant system as a function of drive frequency. The driven resonant system has some natural frequency fo, and the response curve has some characterstic width called the FWHM. the ratio of fo to the FWHM times 2pi gets a pretty good intuition for the Q factor. The Q factor also turns out to relate to the number of oscillations the damped resonant system can undergo - more quality means less oscillations.