We often get the question: What is the difference between a G-string and a thong? The simple answer to this question is: There is no difference. A G-string is a thong type.
The longer explanation tells us that thongs/strings come in many types. Wikipedia describes it as a piece of underwear where the material at the back is reduced to a minimum.
A G-string, as a type of thong, is mostly thinner than a normal thong and has thin laces at the back
There is a exeption: In Australia each G-string is a thong and each thong refers to a slipper.