Source : Webster's Revised Unabridged Dictionary (1913)

Thong \Thong\, n. [OE. thong, [thorn]wong, thwang, AS.
   [thorn]wang; akin to Icel. [thorn]vengr a thong, latchet.
   [root]57. Cf. {Twinge}.]
   A strap of leather; especially, one used for fastening
   anything.

         And nails for loosened spears, and thongs for shields,
         provide.                                 --Dryden.

   {Thong seal} (Zo["o]l.), the bearded seal. See the Note under
      {Seal}.