Butter is available in 1-pound solid blocks, according to the Wisconsin Milk Marketing Board. This is usually what is meant by a "block of butter." Butter is more commonly sold in sticks, with four sticks packaged together to total 1 pound.
Butter is also available in tub form, usually whipped with air or nitrogen, making it easier to use as a spread for breads or muffins. Butter is a compound made from the fat and protein in milk or cream. It can be made with or without salt or added coloring. It usually contains 80 percent or more milkfat. It takes around 11 quarts of milk to make 1 pound of butter.