A person with very light (almost white) blond hair, "tow" being flax or hemp fibers. Tow-headed, along with fair(-haired) and flaxen-haired, is a tradional way in the English language to refer to blond hair or lightly-colored hair, having come from its old Germanic roots (which are quite rare).

tow headed is literally "flaxen haired". This meaning of tow comes from Middle Low German touw (which means "flax, hemp fiber"). This probably went back to the prehistoric Germanic base *tow-, *taw "make, prepare" (source also of English tool), in the sense "make yarn from wool; spin".