The Collaborative International Dictionary of English v.0.48:

Clank \Clank\ (kl[a^][ng]k), n. [Akin to clink, and of imitative
   origin; cf. G. klang sound, D. klank. Cf. Clang.]
   A sharp, brief, ringing sound, made by a collision of
   metallic or other sonorous bodies; -- usually expressing a
   duller or less resounding sound than clang, and a deeper and
   stronger sound than clink.
   [1913 Webster]

         But not in chains to pine,
         His spirit withered with tyeur clank.    --Byron.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clank \Clank\, v. t. [imp. & p. p. Clanked; p. pr. & vb. n.
   Clanking.]
   To cause to sound with a clank; as, the prisoners clank their
   chains.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clank \Clank\, v. i.
   To sound with a clank.
   [1913 Webster]

WordNet (r) 3.0 (2006):

clank
    n 1: a loud resonant repeating noise; "he could hear the clang
         of distant bells" [syn: clang, clangor, clangour,
         clangoring, clank, clash, crash]
    v 1: make a clank; "the train clanked through the village"