noun
(nautical) The top of a mast.
(US) A list of a newspaper or other periodical's main staff, contributing writers, publisher, circulation, advertising rates etc.
(UK, Australia) The title (normally in a large and distinctive font) of a newspaper or other periodical at the top of the front page; (by extension) the publication itself or the rights to it.
(television, by extension) The logo of a broadcaster used in an ident.
verb
(transitive, nautical) To send to the masthead as a punishment.
(transitive) To furnish (a newspaper) with a masthead.