`  == ``Tendency`` ? ==  The lead definition says that resonance is a 'tendency', but in numerous other places (even the second paragraph of the lead), resonance is said to 'occur', or the word 'phenomenon' is used.  I would like to suggest that 'tendency' is inappropriate in the definition; if taken literally it seems to indicate that resonance is a property of a system, whereas in fact it is better to say that resonance is something that happens - it is a phenomenon which certain systems sometimes exhibit.  I would like to suggest this - paraphrased from ``Physics for scientists and engineers - 4th edition, RA Serway, 1996, Saunders College Publishibng, Philadelphia, etc, p 508:  ``A wide range of physical systems, including stretched strings, organ pipes, inductor-capacitor circuits, etc, are capable of oscillating in one or more modes of natural oscillation.  If such a system is made to oscillate artificially by applying an appropriate stimulus, then the resulting amplitude of oscillatory response is greatest when the frequency of the stimulus is equal, or nearly equal to one of the natural frequencies of the system. This form of frequency-selective response is called resonance, and the frequency at which the maximum response occurs is the resonant frequency``.    `