Bascially a can bus is one that permits the passengers to consume cans of beverage whilst onboard. Its most commonly used as a school bus as kids tend to drink cans of soda on the way to school.
In the US the term "can" is sometimes used as slang for the bathroom. In that case, I believe the "CAN bus" best describes the sewerage system of a city. Each home being a node and each toilet, urinal or bidet being an addressable point at the node. In this producer/consumer network, there are usually a multitude of producers and only one main consumer (the sewerage treatment facility). Occasionaly, during storms with heavy rains and flooding, the system becomes overloaded, the flow of data is reversed and the CAN bus is said to be full of sh**.
Actually the Can bus will always take you on a positive ride and the Can't bus is always a negative ride. (Sometimes grounded but usually un-grounded.)
When IF I get going on my electric vehicle project I will probably learn more about CANbus. Right now my only knowledge is that it is used to have vehicle components "talk with each other"