Hotbox or hot box may refer to: 1  A hotbed (gardening) that is enclosed in a box with a glass or clear plastic lid. 2  Hot box, an overheated journal box on a railroad car.3  Hot box (game) , a half-court flying disc sport with a very small box-shaped scoring area.otbox or hot box may refer to: 1  A hotbed (gardening) that is enclosed in a box with a glass or clear plastic lid. 2  Hot box, an overheated journal box on a railroad car.