(For me, the big thing about trams and trains and subways, etc is that the track is a kind of social construct - the track tells me that eventually a vehicle will come for me - no need to really worry about timetables, etc. A bus, a bus may come, maybe it won't. It's all psychoillogical but it's there the same.)
The fundamental operational principle is different. Trams operate (typically, on street running sections) on sight - they are responsible for monitoring traffic, and stoping if necessary. Contrast with the block-based approach used for trains, especially in combination with Euro-style positive train control systems.
Ceci n'est pas une tram: https://www.youtube.com/shorts/kMUANU9H6aw
https://en.wikipedia.org/wiki/Rubber-tyred_metro and https://en.wikipedia.org/wiki/Guided_bus also exist.
(For me, the big thing about trams and trains and subways, etc is that the track is a kind of social construct - the track tells me that eventually a vehicle will come for me - no need to really worry about timetables, etc. A bus, a bus may come, maybe it won't. It's all psychoillogical but it's there the same.)