1. (n.) Prolonged Quality and richness of tone or emotion; as powerful, resonant words\.

2. (n.) A prolongation or increase of any sound, either by reflection, as in a cavern or apartment the walls of which are not distant enough to return a distinct echo, or by the production of vibrations in other bodies, as a sounding-board, or the bodies of musical instruments.

amplitude antinode crest de Broglie wave diffraction electromagnetic radiation electromagnetic wave fluctuation frequency frequency band frequency spectrum guided wave harmonic motion in phase interference libration light longitudinal wave mechanical wave node nutation oscillation out of phase pendulation period periodic wave periodicity radio wave ray reinforcement resonance frequency seismic wave shock wave sound wave surface wave tidal wave transverse wave trough vacillation vibrancy vibratility vibration wave wave equation wave motion wave number wavelength wavering