Tenancy in severalty: Severalty mean a condition of being separate. This gets a lot of people confused because of our use of the word several which would indicate more than two. You will see this type of ownership held by an individual or corporation.
Tenancy in common: This type of ownership allows for both equal and unequal ownership between multiple parties. If an owner passes away their ownership interest is conveyed to their heirs.
Joint tenancy: There are four unities that must exist for joint tenancy which are interest, possession, time and title. Unlike Tenancy in common, joint tenancy has each owner holding the same (interest). They share in an undivided interest (possession) and they receive their interest at the same time (time). Title will require that owners acquire their interest with the same deed (title).
If an owner passes away their interest reverts to the other owners called the right of survivorship.
Tenancy by the entirety: Ownership allowed for married couples. The right of survivorship exists and in some states additional privileges can be merited such as better asset protection.