A dairy is a place where milk is stored and where butter, cheese and other dairy products are made, or a place where those products are sold.^{: 325 : 284} It may be a room, a building or a larger establishment.^: 284 In the United States, the word may also describe a dairy farm or the part of a mixed farm dedicated to milk for human consumption,^: 284 whether from cows, buffaloes, goats, sheep, horses or camels.

The attributive dairy describes milk-based products, derivatives and processes, and the animals and workers involved in their production, for example dairyman, dairymaid, dairy cattle or dairy goat. A dairy farm produces milk and a dairy factory processes it into a variety of dairy products. These establishments constitute the global dairy industry, part of the food industry.