Grants are a form of financial aid. Grants are monies that do not have to be repaid by the student. A grant is awarded to a student who show a financial need. There are different types of grants. There is a federal Pell Grant; the student must meet financial needs requirements of the FAFSA (federal student aid; a part of the department of education) and while in receipt of the grant meet other guidelines including satisfactory academic progress.
There are other grants including specific state grants.
Most forms of financial aid will not cover all of the costs of education, so you may need to have a combination of programs. If you are needing financial aid to attend college, consider applying for a grant.