1bun·ker 
/ˈbʌŋkɚ/ noun
plural bun·kers /ˈbʌŋkɚ/ noun [count] 1 : a strong building that is mostly below ground and that is used to keep soldiers, weapons, etc., safe from attacks
▪ The ammunition is stored in concrete bunkers. — see also bunker mentality 2 golf : an area on a golf course that is filled with sand : sand trap
▪ a fairway bunker 3 : a container for holding coal, oil, etc., on a ship or outside a house
▪ a coal bunker
▪ The ammunition is stored in concrete bunkers. — see also bunker mentality
▪ a fairway bunker
▪ a coal bunker
