A coolbox is a hard box you take on a picnic, to the beach, or on a long drive. You put ice or ice packs in with the food and drinks, and the box keeps them cold and fresh for hours. British English likes coolbox (or cool box); American English almost always says cooler. It does not make things cold by itself — though actually people talk as if it did. It only slows the heat getting in. If you forget the ice, it is just a box. The word is ordinary and practical, not slang. An older phrase, icebox, once meant the kitchen cabinet people used before fridges; that is a different thing.

冰桶、保冷箱（野餐、露營用的那種）