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}.