Coolant is a fluid used in cutting operations, such as those performed on band saws and mill drill machines, to reduce friction, dissipate heat, and remove chips and debris from the cutting area. Coolants can be water-based, oil-based, or synthetic, and may also contain rust inhibitors, biocides, or other additives to improve performance and longevity. Proper coolant usage can prolong tool and blade life, improve cutting accuracy, and prevent overheating or damage to the workpiece.