Evolution of a word

When I was younger, we called the type of sandals that keep falling off because they are designed really badly "thongs." But a thong now usually means one of these, so those sandals get called flip flops to avoid confusion. But Gucci makes flip flops and calls them thongs. I'm so confused. The worst part is that I actually think the Gucci flip flops look cool. I must be going mad.

The Online Etymology Dictionary (via Debbie) says:

thong - O.E. þwong "thong," from P.Gmc. *thwangaz, from a root meaning "to restrain." As a kind of sandal, first attested 1967; as a kind of bikini briefs, 1990s.