When two people buy a property together and one dies, full ownership automatically belongs to the other. What is this called?

The scenario described pertains to the concept of joint tenancy. In a joint tenancy, two or more individuals hold ownership of a property together with equal rights, and it comes with a right of survivorship. This means that if one owner dies, their share of the property automatically transfers to the surviving co-owner(s) without going through probate. This legal arrangement is designed to ensure that the property does not become part of the deceased owner's estate and provides a clear and immediate transfer of ownership to the surviving owner.

In contrast, tenancy in common allows for multiple owners to hold shares of the property independently, meaning that when one owner passes away, their share goes to their heirs rather than automatically transferring to the other co-owners. Tenancy at sufferance refers to a situation where a tenant continues to occupy a property after their lease has expired without the landlord's permission. Community property typically relates to property acquired during marriage and does not apply here since it doesn't specifically address the right of survivorship in the same way joint tenancy does.