The hobo nickel is a sculptural art form involving the creative modification of small-denomination coins, essentially resulting in miniature bas reliefs. The US nickel coin was favored because of its size, thickness and relative softness. However, the term hobo nickel is generic, as carvings have been made from many different denominations. Due to its low cost and portability, this medium was particularly popular among hobos, hence the name "hobo nickel."