The word 罐头 is formed by combining the character 罐, which means "jar" or "can" (the container), with the character 头, which here functions as a nominalizing suffix that indicates a concrete object or item. Together, they semantically shift from the literal "jar head" or "top of a jar" to conceptually represent the entire sealed vessel and, by metonymy, its contents, specifically, food that has been processed and preserved within that can or jar.