The term 'HOPS OR MALT KILN' is a crossword solution for the word 'OAST', which is a four-letter word. An OAST is a kiln used in the brewing process to dry hops or malt. The kiln is usually a tall, cylindrical structure with a conical roof and ventilation holes at the base. The hops or malt are placed inside the kiln and heated to a specific temperature to dry them out. The dried hops or malt are then used in the brewing process to add flavor and aroma to beer.