What is the term for a lease that can be terminated at will by either party without any fixed term?

The term for a lease that can be terminated at will by either party without any fixed term is known as an estate at will. This type of lease agreement does not have a specified duration, which means that either the landlord or the tenant can terminate the lease at any time, as long as they provide appropriate notice. This flexibility is a key characteristic of an estate at will and differentiates it from other lease types that have fixed terms or specific renewal conditions.

In contrast, an estate for years is defined by a specific and fixed duration, which necessitates the lease to continue until the designated end date. A period to period lease is one that automatically renews at the end of each period (like a month-to-month rental), providing less flexibility than an estate at will. A tenancy at sufferance arises when a tenant remains in possession of the property after the lease has expired, which does not reflect the mutual agreement and termination ability characteristic of an estate at will. Thus, the correct term for a lease that can be terminated at will without a fixed term is indeed an estate at will.