The term 'not merely warm' can be summarized by the crossword solution 'BOIL', which is a four-letter word. Boiling is a process of heating a liquid until it reaches its boiling point, which is 212°F (100°C). Boiling is used to cook food, sterilize equipment, and create steam for power generation. Boiling is also used to separate mixtures of liquids and solids, as the solids will remain at the bottom of the container while the liquid boils off.