thong / [unvoicedth]ông; [unvoicedth]äng/ • n. 1. a narrow strip of leather or other material, used esp. as a fastening or as the lash of a whip.2. an item of clothing fastened by or including such a narrow strip, in particular: ∎  a skimpy bathing suit or pair of underpants like a G-string. ∎ another term for flip-flop (sense 1).• v. [tr.] archaic flog or lash (someone) with a whip.DERIVATIVES: thonged adj.thong·y adj.

thong OE. þwang, þwong (þong XIII) = MLG. dwank constraint, OHG. dwang rein (MHG. dwanc, twanc, G. zwang), f. Gmc. *þwang-.