The crossword solution for the term 'watery part of milk' is 'WHEY'. WHEY is a by-product of cheese production and is composed of lactose, minerals, and proteins. It is a liquid that is left over after milk has been curdled and strained. WHEY is often used as an ingredient in food products, such as protein shakes and baby formulas. It is also used in some medical treatments, such as wound healing and skin care.