Milk is produced by the mammary glands of mammals. Early lactation milk is colostrum and contains maternal antibodies, protein and lactose. Milk is an emulsion of fat globules within a water based fluid composed of carbohydrates, minerals, proteins etc. (1)

Each fat globule has a membrane made of phospholipids and proteins. The membrane prevent the fat globules from coalescing. Cholesterol, phospholipids, free fatty acids and cholesterol esters are also present in milk. Milk has 4.9% carbohydrate which s mainly lactose. (2)

It also has around 3.5% fat. Milk fat has a complex fatty acid composition and 15 – 20 fatty acids comprise 90% of milk fat. These give the unique flavour to milk fat and butter. Milk fats melt on heating. Whole milk, butter and cream have high levels of saturated fat. (3)

Lactose gives milk its sweet taste and contributes 40% of cow milk calories.
Milk contains water soluble vitamins B1, B2, B3, B5, B6, B12 and folate. It is not a good source of Vitamin C. It contains fat soluble vitamins and the level depends on the fat content of the product.(4)

Milk is a good source of zinc,calcium,magnesium,phosphorus & may also contain white blood cells,mammary gland cells & various bacteria. On standing, milk separates into high fat cream& low fat milk. Milk protein is similar to other animal protein& has high biological value.(5)

Milk and meat products comprise a separate food category (milk, curd, skimmed milk, cheese, paneer, chicken, liver, fish, egg, red meat)
Animal milk, such as undiluted cow’s milk must be given to children after 6 months of age, as it is a good source of several key nutrients. (6)

Milk needed daily range from 200 -370 ml if other animal source foods are eaten & 300 to 500 ml daily if they're not. To meet nutrient needs, animal source foods other than milk are also needed eg 60 g of egg (one egg) and 14 to 75g of meat, poultry, fish or chicken liver. (7)

So milk is not vegetarian. Its COMPOSITION (lactose, cholesterol, protein, fatty acids etc) are similar to ANIMAL SOURCES of food and NOT plants

@UrbanXXpat hope you saw this thread