Filoplume is a technical term in ornithology that refers to a type of feather found among birds. However, there are some synonyms that can be used to describe this type of feather, such as hair feather, accessory feather, or thread feather. These feathers are found in many bird species, and they serve various functions such as insulation, decoration, and sensory perception. They are characterized by their simple structure, with a thin, central shaft and a few short, hair-like barbs. Filoplumes may not be readily apparent to the naked eye, but they play an essential role in the functioning of the feathered body of birds.