What is the English word marta la dominadora?

The phrase "Marta la dominadora" is Spanish, not English. It literally translates to "Marta the Dominant," but it's not a common English phrase.

To understand the full meaning, you need more context. Depending on the situation, it could be:

* A nickname: A nickname for a person named Marta who is assertive, controlling, or powerful.

* A title: A title given to a person named Marta who has a role of dominance in a certain area.

* A descriptor: A way to describe a person named Marta who displays dominant traits.

Without more information, it's difficult to give a precise English equivalent.