See https://www.irs.gov/charities-non-profits/private-foundations/grants-to-individuals
Without knowing what you received (grant? fellowship? award?) and what it was designated for (if anything) it's just a wild guess at this point. It would help also if you let us know if you received any type of tax reporting document with the amount of the grant on it, or if you received a letter addressing and specifying the purpose and use of the money. (if such a letter was received)
