Sole, separate and joint tenants
Sole tenancies - if you rent a property by yourself then you will be a sole tenant, with the sole responsibility to pay the rent and other costs that you are liable for, for example council tax and utilities. These are normally highlighted in the agreement.
Separate tenancies - if you live in a communal setting (such as a House in Multiple Occupation) but your landlord got you all to sign individual leases, then you will have a separate tenancy, which means you will only be liable for the rent that is noted on your agreement and not for the whole of the property. However, the tenenacy agreement may state that you have to jointly pay the council tax and bills with the other tenants in the property.
Joint tenancies - if you share a property with other people and you have all signed the same tenancy agreement, then you will be a joint tenant. Joint tenants are jointly liable for rent and any other obligation that they agreed to by signing an agreement.