"Havaianas" in Portuguese means "Hawaiian women" (if the name was "Hawaiian men", it would be called "HavaianOs").
Because of its cheap material, easy, and quick production, these thongs a few years ago used to get to the market for a very cheap and accessible price, therefore its main consumers were Brazilians from classes C and D. Today Havaianas are very popular, world wide known, and its price can get very expensive in some countries, as France, and Italy.
Anyway... Its cool website is also Brazilian (design) made:
http://www.havaianas.com.br/#