Primary Sourcesare used in a variety of disciplines, and the definition may vary depending on your course. Generally, aprimary sourceis a first-hand account of an event, period, era, etc. For example, a newspaper article published in the 1860s describing a Civil War battle would qualify. It may also be an original source; a poem could be theprimary source, whereas a critical analysis of the poem would be thesecondary source.
