According to Davenport University, a diploma is equivalent to a GED certificate or completed homeschooling at the secondary level. GED refers to General Education Development.
Dictionary.com defines a diploma as a document provided to a student by an educational organization to indicate the satisfactory completion of a course of study. Federal regulations require that an individual applying for federal financial aid at a post-secondary institution must provide a high school diploma or equivalent to be eligible. These regulations also hold that a high school diploma from a foreign school is acceptable if it is deemed equivalent to a U.S. high school diploma.