dou·ble–deck·er 
/ˌdʌbəlˈdɛkɚ/ noun
plural dou·ble–deck·ers /ˌdʌbəlˈdɛkɚ/ noun [count] : something that has two levels or layers
▪ The bus we rode on was a double-decker. — usually used before another noun ▪ We took a tour of London on a double-decker bus. ▪ double-decker trains ▪ a double-decker sandwich — compare single-decker, triple-decker
▪ The bus we rode on was a double-decker. — usually used before another noun ▪ We took a tour of London on a double-decker bus. ▪ double-decker trains ▪ a double-decker sandwich — compare single-decker, triple-decker
