What term describes someone who is the sole owner of a tract of realty?

The correct term for someone who is the sole owner of a tract of real estate is "Owner in Severalty." This term specifically refers to an individual who holds title to a property independently, without any co-owners or partners. Ownership in severalty means the owner has complete control over the property and is entirely responsible for all rights and obligations associated with it, such as paying property taxes, maintaining the property, and making decisions regarding its use or potential sale.

In contrast, joint tenants share ownership with others, typically in a way that includes rights of survivorship. A beneficiary typically refers to someone who receives benefits from a trust or estate. A trustee is a person or entity that holds and manages property or assets for the benefit of others, and does not necessarily have ownership rights. Each of these other terms indicates some level of shared responsibility or shared ownership, whereas "Owner in Severalty" clearly defines the status of sole ownership.