What does the term 'Pennants' refer to in military flags?

The term 'Pennants' in the context of military flags most accurately refers to a triangular flag used for various utility purposes. Pennants often serve as visual signals in maritime contexts or within military operations, and their distinct shape allows them to be easily recognized at a distance. This triangular form can provide different meanings depending on the context in which it is used, such as denoting a specific status, a warning, or signaling to other units.

The other options describe different types of flags or their uses, but they do not encompass the specific characteristics and applications associated with pennants. A rectangular flag for ships, for example, serves a different functional purpose in maritime operations, while a swallow-tailed flag typically denotes organizational or unit identification rather than the multi-purpose functionality of a pennant. Lastly, flags flown from land installations refer to stationary indicators rather than the more versatile use of pennants in various operational contexts.