Crosshaid or Crosshead: How To spell?

The word Crosshaid is misspelled against Crosshead, a noun meaning "A beam or bar across the head or end of a rod, etc., or a block attached to it and carrying a knuckle pin; as the solid crosspiece running between parallel slides, which receives motion from the piston of a steam engine and imparts it to the connecting rod, which is hinged to the crosshead."