A leasehold estate is defined as a/an _____ estate which is insurable.

A leasehold estate is best defined as an equitable estate, which reflects the rights of a tenant to use and occupy property under the terms of a lease agreement. In the context of title insurance, leasehold estates are particularly important because they involve an agreement between a landlord and a tenant, giving the tenant certain legal rights to the property for a specified duration.

Equitable estates arise because the tenant may possess a right or interest in the property that is distinct from the actual ownership of the property itself. This distinction allows the leasehold estate to be insurable, as title insurance can provide coverage for the rights of the tenant.

In contrast, a fee estate conveys full ownership rights and holds different implications under title insurance. A remainder estate refers to a future interest in property that will become possessory upon the termination of another interest, while entireties represent property held by married couples with specific rights of survivorship. Neither of these concepts fully encapsulates the nature of a leasehold estate as an insurable interest. Therefore, the emphasis on the "equitable" nature of a leasehold estate leads to its classification as insurable, confirming the correctness of selecting "equitable" in this context.