Co-borrower

What Does Co-borrower Mean?
Any additional borrower(s) whose name(s) appear on loan documents and whose income and credit history are used to qualify for the loan. Under this arrangement, all parties involved have an obligation to repay the loan. For mortgages, the names of applicable co-borrowers also appear on the property's title.

Investopedia explains Co-borrower
A co-borrower is different that a cosigner in that a cosigner takes responsibility for the debt should the borrower default, but does not have ownership in the property. Co-borrowers are frequently spouses or partners who use their combined income to qualify for a larger mortgage than could be obtained singularly, and are willing to share the risk of default on the mortgage and the general risks of homeownership.