Read the Library of Congress definition of a primary source:
Primary sources are the raw materials of history — original documents and objects which were created at the time under study. They are different from secondary sources which are accounts or interpretations of events created by someone without firsthand experience.
Read the Yale University definition of a primary source:
Primary sources are original materials on which other research is based.They are from the time period involved and have not been filtered through interpretation or evaluation. Primary sources are usually the first formal appearance of results in physical, print or electronic format. They present original thinking, report a discovery, or share new information.
