The term 'back financially' can be broken down into three crossword solutions: SPONSOR (7 letters), ENDOW (5 letters), and FUND (4 letters). Sponsoring is the act of providing financial support for a person or organization, usually in exchange for publicity or other benefits. Endowing is the act of providing a large sum of money to an organization, often with the intention of creating a lasting legacy. Finally, funding is the act of providing money for a particular purpose, such as a project or venture. All three of these terms refer to providing financial support, and together they can be used to describe the concept of backing someone or something financially.