A more thorough explanation:

Definition: Do (doh) is a Latin term that means "I give." In history, it was considered the oldest and most appropriate way to effect a feoffment and gift.

Example: A lord might say to a vassal, "I do give you this land," using the term "do" to indicate the act of giving.

This example illustrates how the term "do" was used in the context of feudalism, where lords would grant land to their vassals as a reward for their loyalty and service. By saying "I do give you this land," the lord was making a formal declaration of the gift, using the traditional language of feoffment.