The Suze asks: "Why do we call homeless people hobos? Where does that word come from?"

First, let's get one thing straight: most of the people we call hobos are not actually hobos.  They are either tramps or bums.  Yes, there is a difference.  The guys we see sitting under the overpasses? Those are bums (or, in the parlance of Houston, "campers").  They are non-itinerant non-workers.  A tramp is an itinerant non-worker.  They travel, but they are not doing so to find work.  A hobo is an itinerant worker.  They have no home, so they travel from place to place looking for work.  They are the most noble of all homeless people. Also? Bindles.

So you and I, the Suze, call those people hobos because we are using the word incorrectly.  However, why are actual hobos called hobos?  Nobody knows for sure, but there are lots of theories. 

It could be a contraction of a two word phrase used to describe them.  Some examples:  Homeward bound.  Houston and Bowery.  Hoe-boy.  Hopping boxcars. Homus bonus (latin for good man).  Homeless body.

It could come from the city of Hoboken, New Jersey, which was a large railway hub in the late 19th century (note that much of hobo lore is centered on the railroad, as this was the preferred mode of travel of your average hobo).

The bo could be an adaptation of either boy or beau; thus, the word hobo would be a contraction of the greeting "Ho, boy!" or "Ho, beau!"

My favorite explanation, however, is this:

"[i]n the course of my study of the Japanese language for military purposes, I came upon the word hobo. In the Japanese, hobo is plural form of ho [which means] 'side'. In the plural it takes the meaning 'all sides' or 'everywhere'. As the meaning seemed to fall in so closely with the current American idea of hobo, I at once felt that here was the original form of the word.... The word originated on the western coast of the United States. This lends further color to the theory of its Japanese origin."