Don is the buyer and Sandra is the seller. On the contract, they are considered the ______.

In a contract, the terms used to identify the primary parties involved are essential for clarity and legal precision. In this scenario, Don and Sandra, as the buyer and seller respectively, are referred to as principals. This is because "principals" denotes the main parties who have the authority and responsibility within the contract. They are the individuals who enter into the agreement and have a vested interest in its execution.

The term "principals" is widely used in legal contexts to distinguish those who take direct action in a transaction from other parties who may be involved for different reasons, such as agents or representatives. By identifying Don and Sandra as principals, the contract establishes them as the central figures who will ultimately benefit from or be held accountable to the terms set forth in the agreement. This usage is consistent across various types of agreements, reinforcing the importance of understanding the roles of each party involved in a contractual relationship.