adj. 1 (of sound) echoing, resounding; continuing to sound; reinforced or prolonged by reflection or synchronous vibration. 2 (of a body, room, etc.) tending to reinforce or prolong sounds esp. by synchronous vibration. 3 (often foll. by with) (of a place) resounding. 4 of or relating to resonance. resonantly adv.
[ F résonnant or L resonare resonant- (as RE-, sonare sound) ]