Meaning of “thong” - Learner’s Dictionary

thong

noun [ C ] us uk /θɒŋ/
underwear

a piece of underwear or the bottom part of a bikini (= a piece of clothing with two parts that women wear for swimming) which does not cover the bottom

shoe US

a flip-flop

(Definition of “thong” from the Cambridge Learner’s Dictionary © Cambridge University Press)