arena
ES [aˈɾena] · Spanish for “sand” · identical to English arena
It took me quite some time to figure out that in Spanish, arena really did not mean the same thing as I expected from English, and other languages. In Spanish, arena stands for sand, whereas in English and other languages, it signifies a venue on which big events take place, such as concerts, sport events, you name it.
Same word, and the English one is hiding its roots. Latin arena (or harena) meant sand. The central floor of a Roman amphitheatre was strewn with sand to soak up the blood, and that floor was called the arena - literally “the sand.” The name spread outward from the floor to the whole venue, and English borrowed that sense: arena = the place. Spanish just kept the grain of it. So whenever you sit in an arena, you are, etymologically, sitting around “the sand” - hardwood floor or not.