* Noun: When it refers to the event or scene itself.
* Example: "The flashback showed the character as a child."
* Verb: When it describes the act of remembering something from the past.
* Example: "The film flashed back to the fateful day."
* Adjective: (Less common) When it describes something related to a flashback.
* Example: "The flashback scene was particularly moving."
It's important to look at the context of the sentence to determine the correct part of speech.