Milk is an opaque white liquid produced by the mammary glands of female mammals (including monotremes.)
It provides the primary source of nutrition for newborn mammals before they are able to digest other types of food. The early lactation milk is known as colostrum, and carries the mother's antibodies to the baby. It can reduce the risk of many diseases in the baby.
The exact components of raw milk varies by species, but it contains significant amounts of saturated fat, protein, and calcium as well as Vitamin C.
Comparison between different types of milk: earthlife.net