A Corporate FD is a fixed deposit scheme offered directly by a company, usually an NBFC (non-banking financial company) or a large corporate, rather than by a bank. Companies raise money this way and, in exchange for lending them your money, typically offer a noticeably higher interest rate than a comparable bank FD of the same tenure.
The higher return comes with meaningfully higher risk: unlike bank deposits, corporate FDs are not insured by the DICGC, so if the company runs into financial trouble, your deposit isn't protected the way a bank deposit up to ₹5 lakh would be. Before investing, it's important to check the company's credit rating from agencies like CRISIL or ICRA — a higher rating (like AAA) signals lower risk of default, though even highly-rated companies aren't entirely risk-free.