Actually here's the real official definition from the Anglo-American Cataloging rules jointly published by the British, Canadian, Australian & American Library Associations, the Libray of Congress and the British Library:

"Title page. A page at the beginning of an item bearing the title proper and usually, though not necessarily, the statement of responsibility and the data relating to publication. The leaf bearing the title page is commonly called the 'title page' although properly called the 'title leaf.'"

Bruce, 'legal page' may be jargon, but librarians have the jargon too.

In newspapers the information in the the 'masthead.' I don't know why a generally usable term for all that stuff in books has never really caught on.