Definition from Nolo’s Plain-English Law Dictionary

Two or more tenants who rent the same property under the same lease or rental agreement. Each cotenant is 100% responsible (also known as joint and severally liable) for carrying out the rental agreement, which includes paying the entire rent if the other tenant skips town and paying for damage caused by the other tenant. In addition, if one cotenant violates the lease or rental agreement, the landlord may evict all of them.

Definition provided by Nolo’s Plain-English Law Dictionary.