Confused about Types of Aquariums

[thalassomalunar]

I am getting mixed up and confused about all the different types of aquariums. Is there a difference between freshwater and tropical freshwater? Are saltwater and reef aquariums the same thing? In general what are all the types of aquariums and what do they mean?

 

[Cactuspixie]

Freshwater encompasses:

Coldwater
Tropical (warm freshwater)
Brackish- (slightly salty water)

Saltwater encompasses:

Reef- corals and fish
FOWLR- fish only with live rock
Marine- just saltwater fish.

That's here in Australia anyway- there may be a slight variation between countries, but that's the gist of it