It can mean:
* Dark: Often used to describe skin color, hair, or other features. This meaning is more common in Latin America.
* Black: This is a less common meaning and is more likely to be used when referring to something being completely dark or black.
* Brown: This is a less common meaning and is often used to describe darker shades of brown.
For example:
* "El hombre prieto" (The dark man) - referring to a man with darker skin.
* "El cielo estaba prieto" (The sky was black) - referring to a very dark sky.
It's important to consider the context when trying to understand the meaning of "prieto" in English.