The metric unit that measures the amount of liquid in an object is the liter (L).

Here are some other important units related to volume:

* Milliliter (mL): 1000 milliliters equal 1 liter. This is a very common unit for measuring smaller amounts of liquid.

* Cubic centimeter (cm³): 1 milliliter is equal to 1 cubic centimeter. This unit is often used in scientific contexts.