The short answer is that these two terms are often used interchangeably, but there are actually differences in the details.
Both loans are short-term, primarily used for real estate investments, and have similarly flexible repayment terms. However, a bridge loan can be funded by either private or institutional lenders, can be secured by assets and/or equity, and has stricter guidelines for how the funds can be used. In contrast, a hard money loan is only funded privately, is secured only by the “hard” real estate asset itself, and can be used for nearly any purpose the lender approves.
These differences mean that a bridge loan can also be a hard money loan, and a hard money loan can also be a bridge loan, but not all hard money loans are bridge loans, and not all bridge loans are hard money loans.
Confused yet? 🙂