I'm shocked at the ruckus my simple question caused. I never imagined anyone would care so much what I'm wearing on my feet. I am a boomer in my mid-fifties and when I was growing up, they were called thongs and "thong sandals" later when thong underwear came around. I agree with the posters who said a flip flop is a flat rubber shoe with a strap between the toes that makes the flip flop sound when you walk. My "flip flops" do not have a flat bottom, they are leather, and they definitely do not make the flip flop sound. I also own a pair of leather sandals that technically meet the dress code standard with a strap around the back, but the shoes I posted are far classier and stylish than those.