Saint Domigue's economy was dependent on

plantations.

What does this mean

Saint Domingue's economy was dependent on plantations. This means that their whole business rotated around these plantations. They were the biggest means of making money, and without it, much of the business would fall. For example, if all of the plantation farms were burnt to the ground, then it would have a huge impact on how much money St. Domingue made. In this event, their business would most likely go downhill until they can rebuild the farms.