What is the term for an estate in land that is owned for an indeterminate length of time?

The correct term for an estate in land that is owned for an indeterminate length of time is referred to as a freehold estate. This type of estate represents ownership of real property for an unrestricted timeframe, meaning there is no set expiration date or end date to the ownership. A freehold estate allows the owner to possess, use, and transfer the property at their discretion, which is a fundamental characteristic of true ownership in real estate.

In contrast, a leasehold estate typically involves renting property for a specified period and does not confer ownership rights beyond the terms of the lease. Similarly, a fee simple estate, while also a form of freehold estate, specifically indicates the highest level of ownership interest possible, including full rights to use and transfer property, but does not alter the general definition that freehold estates encompass. A life estate is limited to the duration of a person's life, which is a defined timeframe and therefore does not fit the requirement of being owned for an indeterminate length of time.