Formal:
* Pennant: This is the most common and accurate term for a long, narrow flag, often used for signaling or identification.
* Streamers: These are long, narrow flags that are often used for decoration.
* Pennon: A small, pointed flag, often used for personal or heraldic purposes.
* Standard: A flag, often rectangular but also elongated, that represents a country, organization, or individual.
* Banner: A large flag, often rectangular but sometimes elongated, that is used for display or as a symbol.
Informal:
* Flag: This is a general term for any flag, but can also be used to refer to a long, narrow one.
* Strip: A simple and informal term for a long, narrow flag or banner.
* Ribbon: This can be used to describe a long, narrow flag or banner, especially if it is made of a soft, flowing material.
* Tail: This is a more informal term for a long, narrow flag, particularly if it is trailing behind something.
The best word to use will depend on the specific context and the type of flag or banner being described.