Casco is a Spanish word that is commonly used to refer to a protective helmet. However, there are several synonyms of this word that are used regionally or in different contexts. For example, in some Latin American countries, the word "chaleco" can be used to refer to a helmet or any other type of protective gear. In some areas, the term "cacha" is used specifically to refer to a military helmet. Other synonyms for casco include "gorra" which refers to a hat-like protective gear that covers the head, "cascó" which is the Catalan equivalent of the word, and "capacete" which is used in Portuguese. Using these synonyms can help to make your language more precise when referring to different types of helmets or protective gear.