What type of source would a diary entry be classified as?

A diary entry is classified as a primary source because it provides firsthand accounts of personal experiences, thoughts, and feelings from the individual who wrote it. Primary sources are original materials that have not been altered or interpreted, allowing researchers to gain direct insight into a person's life and the historical context in which they lived.

In contrast, secondary sources analyze or summarize information from primary sources. They interpret, critique, or synthesize the original materials and often provide context or commentary. Tertiary sources, on the other hand, compile and summarize information from primary and secondary sources, such as encyclopedias or fact-based guides. A documentary source often refers to a collective representation of data or events, often found in films, videos, or written records, but does not apply specifically to individual accounts or personal reflections, such as a diary entry.