Floors of a building re UK English versus U.S. English

Today's Dictionary.com Spanish Word of the Day was "cuarto" as in fourth: cuarto, adjective,
pronoun
fourth
España ocupa el cuarto lugar.
Spain is in fourth
place.

en el cuarto piso
on the fifth floor US , on the fourth floor Britain ..... I have seen this before and I have no idea where the publishers of Dictionary.com got this information but in any city I've ever been the fourth floor is the fourth floor and the fifth is the fifth. Anybody have a different experience?:confused: