1A piece of machinery used to lower a coal wagon from a wharf to the level of a hatchway on a ship so that the coal may be deposited directly into the hold. Now chiefly historical.
2An apparatus for depositing coal into a storage place, container, etc., usually by means of a slide or chute; especially a structure consisting of an elevated section of railway track allowing coal to be dropped directly out of the bottom of a truck or hopper into a receptacle positioned below.
Mid 19th century; earliest use found in Railway Times. From coal + drop.