Your skin type is determined by genetics. There are four basic types: normal, dry, oily & combination skin. Dry skin is characterised by its lack of water & lipids. It, therefore, needs a specific beauty regime. 

With dry skin, the hydrolipid film is not thick enough, the epidermis is permeable, the skin no longer provides a barrier function in the face of external aggressors (cold, wind, pollution) & no longer controls transepidermal water loss.