Definition of "Header" :

noun: a headlong jump (or fall)

"He took a header into the shrubbery."

noun: (soccer) the act of hitting the ball with your head

noun: a machine that cuts the heads off grain and moves them into a wagon

noun: a framing member crossing and supporting the ends of joists, studs, or rafters so as to transfer their weight to parallel joists, studs, or rafters

noun: brick that is laid sideways at the top of a wall

noun: horizontal beam used as a finishing piece over a door or window

noun: a line of text serving to indicate what the passage below it is about