Bandwidth and throughput are closely related but have distinct characteristics. Throughput is a measurement of how much data is transmitted from one point to another within a set amount of time. Bandwidth is a measurement of the amount of data that can be transmitted simultaneously.
To use another analogy, throughput is like the amount of water you can fill in a bucket within a certain amount of time, and bandwidth is like the size of the pipes through which the water is flowing. Wider pipes allow for better water flow, just as more bandwidth allows for more data to be transmitted at once.