Any horse used in horse-cavalry, but especially one bearing an armoured knight.
A regularly revived theatrical or musical work, as with Hamlet or a Beethoven symphony, or as excerpts thereto. May imply that the work in question has become hackneyed.
An experienced person who has been through many battles, situations or contests; someone who has given long service.
A horse used primarily for manual labor; a draft horse.
Anyone or anything that does a lot of work; something or someone who works consistently or regularly.