Hobo is a word for a homeless person who travels to different cities and towns to look for work. Hobos usually travel by train "hopping" (riding in empty train freight railcars without paying for a ticket), or sometimes "riding the rods" (lying dangerously near the train wheels, underneath the cars).
Hobos stay in very cheap hotels in cities, or camp in simple shelters (" ") in shanty towns near the rail yards. There were many hobos during the Great Depression in the United States because many people lost their jobs and homes. Many people blamed President Herbert Hoover for the Depression, so hobo camps were sometimes called "Hoovervilles".