The word means literally 'running headline'. This is an old printing style, using a repeated heading on each page of a newspaper, magazine, book or other document. The running head was usually an ornamental font, or decorated, until the advent of the paperback, where it became more utilitarian. It was commonly used for chapter titles, but over time it was considered too expensive, and replaced with title pages listing chapters and in some cases chapter summaries. A running head is still sometimes used in authentic reproductions of old books and children's books. The style still appears occasionally in report writing, as an organizational motif for subjects.
Examples of Running Head: