Here's why:
* Concrete nouns refer to things that can be perceived by the senses (sight, touch, smell, taste, hearing).
* While ghosts are supernatural and cannot be physically touched, they are often described with physical attributes (like appearing as a translucent figure or making noises). This makes them tangible in a conceptual sense.
Abstract nouns, on the other hand, refer to ideas, concepts, or qualities that cannot be perceived by the senses. Examples include happiness, love, or justice.
Let me know if you have any other words you want to categorize!