Is department store a common noun or compound noun?

"Department store" is a compound noun, as it is made up of two Words, "department" and "store," that together refer to a specific type of retail establishment. Each part retains its own meaning, but when combined, they create a new concept. While "department store" can also be considered a common noun because it refers to a general category of stores rather than a specific brand, its compound nature is what defines it grammatically.