Poliosis is a decrease or absence of melanin (or color) in the scalp, eyebrows, eyelashes, or any other hairy area. It is commonly known as a white forelock when it affects the hair just above the forehead.
My husband has a buddy with whom he`s been friends since grade school who has this. His is in the front of his hair. My friend`s baby (now 35) has it as well,but hers is at the crown. I never knew what it was called.