Meaning of header

head•er

1. a person or thing that removes or puts a head on something.
2. a reaping machine that cuts off and gathers only the heads of the grain.
3. a chamber to which the ends of a number of tubes are connected so that water or steam may pass freely from one tube to the other.
4. an exhaust manifold.
1. a brick or stone laid in a wall or the like so that its shorter ends are exposed or parallel to the surface. Cf. stretcher (def. 5).
2. 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.
6. a plunge or dive headfirst, as into water: He stumbled and took a header into the ditch.
7. a pass or shot made by heading the ball.
8. a sign that is part of or attached to the top of a rack displaying merchandise.
9. a line of information placed at the top of a page for purposes of identification.