Final answer:
A textbook or a manual can be considered both a secondary source and a tertiary source in history.
Step-by-step explanation:
A tertiary source that can also be considered a secondary source is a textbook or a manual.
The distinction between primary and secondary sources is not fixed, as a document can be both a primary and secondary source depending on its use. For example, a biography written by a scholar about an artist would be a secondary source about the artist and a primary source about the scholar. Similarly, a secondary source can also be a
literary criticism that evaluates published work rather than presenting original research.