1) Brush 
[cave formation] Bottlebrushes are an uncommon cave formation which result from a rise in water level such that the stalactites become immersed. If the water is supersaturated with calcium carbonate the stalactite will become coated with pool spar. ...
(from the article `Callistemon`) genus of shrubs and trees, of the family Myrtaceae, native to Australia. They have spikes of showy flowers and are commonly called bottlebrushes. The ...
(Callistemon) This group consists of tender, evergreen shrubs and small trees that are natives of Tasmania and Australia. Commonly known as Bottlebrushes, these attractive plants produce spikes of colorful flowers, of which the most conspicuous parts are the tufts of long stamens. These flower spikes resemble bottlebrushes, thus the common name. A....
[n] - a cylindrical brush on a thin shaft that is used to clean bottles
noun a cylindrical brush on a thin shaft that is used to clean bottles
any of various trees or shrubs of the myrtle family, esp. of the genera Callistemon and Melaleuca, native to Australia and adjacent areas, having spikes of flowers with numerous conspicuous stamens.