1. James Wolcott 2. The increase in amplitude of oscillation of an electric or mechanical system exposed to a periodic force whose frequency is equal or very close to the natural undamped frequency of the system. 3. Intensification and prolongation of sound, especially of a musical tone, produced by sympathetic vibration. 4. Intensification of vocal tones during articulation, as by the air cavities of the mouth and nasal passages. 5. The sound produced by diagnostic percussion of the normal chest. 6. The property of a compound having simultaneously the characteristics of two or more structural forms that differ only in the distribution of electrons. Such compounds are highly stable and cannot be properly represented by a single structural formula.
