The word ‘curbstone’ can refer to a couple of different concepts:
1. **Physical Definition**: A curbstone is a stone or a brick that forms the upper edge of a curb, which is the raised edge of a street or sidewalk. It serves as a boundary between the road and pedestrian pathways.
2. **Figurative Definition**: In a more figurative sense, ‘curbstone’ can refer to something that is informal or amateurish, particularly in contexts like finance or business, where decisions or opinions are made without formal analysis or expert input.
Overall, the context in which the term is used will determine its specific meaning.