In the well-known nursery rhyme, Humpty Dumpty is an egg who falls off a wall and shatters. The poem is often used as a metaphor for something that is broken beyond repair. In other words, once something has been Humpty Dumpty-ed, it can't be put back together again.
This interpretation of the poem likely comes from the line All the king's horses and all the king's men / Couldn't put Humpty together again. It's often assumed that this means that no one can fix what's been broken.
However, some people believe that the poem isn't about an egg at all, but rather about King Richard III of England. In this interpretation, Humpty Dumpty refers to Richard III's body after he was killed in battle and his kingdom fell apart. This theory is based on the fact that some versions of the rhyme include the lines York came down, / And Warwickshire rose up. These lines are thought to refer to the Battle of Bosworth Field in 1485, which saw Richard III defeated by Henry Tudor (the future Henry VII). After Richard III's death, Henry Tudor became king and began the Tudor dynasty.
So, while there is no definitive answer to what Humpty Dumpty really means, there are two popular interpretations of this classic nursery rhyme.