The unit of density for liquid (and for solids and gases too) is typically kilograms per cubic meter (kg/m³).

Here are some other common units of density:

* grams per cubic centimeter (g/cm³): This is a very convenient unit for liquids, as 1 g/cm³ is equal to 1000 kg/m³.

* pounds per cubic foot (lb/ft³): This is often used in the US.

* grams per milliliter (g/mL): This is equivalent to g/cm³ and is also commonly used for liquids.

It's important to note that the unit of density can vary depending on the context and the specific application.