|part of speech:
||a person or machine that puts heads on something, such as nails, rivets, and the like.
||(informal) a headfirst dive or fall.
He took a header off the roof.
||a brick or stone laid across a wall so that its short end is exposed. (Cf. stretcher.)
||in word processing or printing, information that is repeated at the top of a sequence of pages. (Cf. footer.)
||a pipe or tube that brings together several pipes or tubes, as at an exhaust manifold.