A leasehold that is termed as a "month-to-month tenancy" is most likely which type of estate?

A month-to-month tenancy is classified as a periodic estate. This type of estate is characterized by a rental agreement that renews automatically at the end of each period—typically a month in this case—until either the landlord or tenant provides notice to terminate the arrangement. The key feature of a periodic estate is this automatic renewal based on defined intervals, which can be days, weeks, months, or even years.

In contrast, an estate for years has a specific starting and ending date and does not automatically renew. An estate at will is more indefinite and can be terminated at any time by either party, typically requiring less formal notice. Lastly, a tenancy at sufferance arises when a tenant remains in possession after the lease has expired and does not have the landlord's consent to stay, which is not applicable in a month-to-month tenancy scenario where the terms are clearly defined and accepted by both parties. Thus, the nature of a month-to-month agreement aligns with the characteristics of a periodic estate.