The Collaborative International Dictionary of English v.0.48:

Reverberation \Re*ver`ber*a"tion\, n. [CF. F.
   r['e]verb['e]ration.]
   The act of reverberating; especially, the act of reflecting
   light or heat, or reechoing sound; as, the reverberation of
   rays from a mirror; the reverberation of rays from a mirror;
   the reverberation of voices; the reverberation of heat or
   flame in a furnace.
   [1913 Webster]

WordNet (r) 3.0 (2006):

reverberation
    n 1: the repetition of a sound resulting from reflection of the
         sound waves; "she could hear echoes of her own footsteps"
         [syn: echo, reverberation, sound reflection,
         replication]
    2: a remote or indirect consequence of some action; "his
       declaration had unforeseen repercussions"; "reverberations of
       the market crash were felt years later" [syn: repercussion,
       reverberation]

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "reverberation":
   acknowledgment, action and reaction, answer, answering, antiphon,
   automatic reaction, autonomic reaction, back answer, back talk,
   backchat, boom, booming, bounceback, comeback, echo, evasive reply,
   growl, growling, grumble, grumbling, predictable response,
   reaction, ready reply, reboation, rebound, receipt, reecho,
   reflection, reflex, reflex action, refluence, reflux, rejoinder,
   repartee, replication, reply, repost, rescript, rescription,
   resound, resounding, respondence, response, responsion, responsory,
   retort, retroaction, return, revulsion, riposte, rise, rumble,
   rumbling, short answer, snappy comeback, thunder, thundering,
   unthinking response, witty reply, witty retort,
   yes-and-no answer