Generally speaking, yes.
HOWEVER, terrariums were not necessarily built to hold water so you run the risk of a catastrophic leak or even losing the entire contents.
My advice would be to NOT use a terrarium as an aquarium. But many have and have had no problems.
If you are tempted to try, check the terrariums seams where the pieces of glass come together. If they are sealed tight with silicone (like an aquarium) at ALL joints, this is a good sign. Fill it slowly with water, checking for leaks all the while. If you see a leak, then abandon the project.
Just remember, you fill a terrarium with water at your own risk.
For instance you go to a red lobster and they have a tank full of lobsters nothing fancy and you go to a museum and they have a fancy aquarium filled with coral reefs and exotic fish. So, a tank is a simple bowl or small tank, lets say less than 10 gallon with a goldfish and gravel. An aquarium is more than 10 gallons with plants, fancy lighting, and exotic fish.
Tank=simple
Aquarium=Fancy
In the fishkeeping world there is no difference. A Fish Tank is an Aquarium. Of course a Tank is simply a container and can be anything from a war machine to a container for petrol on a car.
an aquarium
Aquarium is another name for a fish tank
Fish tank
Fishing in an aquarium; aquarium fishing is when you scoop fish out of your tank with a net.
Aquarium as in fish-tank means "Aquarium"
An aquarium
Aquarium.
Aquarium is another name for a fish tank
Aquarium .
They are kept in a fish shop or aquarium or even a fish tank
The general rule for stocking a fish tank is 1 inch of fish per gallon of aquarium water.