The term "ice cubes" refers to small, solid blocks or pieces of ice that are typically used for cooling drinks. These can be made at home by filling a tray with water and placing it in the freezer until the water has frozen into ice cubes. They come in various sizes and shapes depending on the type of mold they were formed in, but generally speaking, an "ice cube" is any small piece of solidified water that can be used to chill a drink or other food items.