Bristle in the context of Brushes

A brush is a common tool with bristles, wire or other filaments. It generally consists of a handle or block to which filaments are affixed in either a parallel or perpendicular orientation, depending on the way the brush is to be gripped during use. The material of both the block and bristles or filaments is chosen to withstand hazards of its intended use, such as corrosive chemicals, heat or abrasion. It is used for cleaning, grooming hair, make up, painting, surface finishing and for many other purposes. It is one of the most basic and versatile tools in use today, and the average household may contain several dozen varieties.

In biology, setae (/ˈsiːtiː/; sg. seta /ˈsiːtə/; from Latin saeta 'bristle') are any of a number of different bristle- or hair-like structures on living organisms.

Baleen is a filter-feeding system inside the mouths of baleen whales. To use baleen, the whale first opens its mouth underwater to take in water. The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as a food source for the whale. Baleen is similar to bristles and consists of keratin, the same substance found in human fingernails, skin and hair. Baleen is a skin derivative. Some whales, such as the bowhead whale, have baleen of differing lengths. Other whales, such as the gray whale, only use one side of their baleen. These baleen bristles are arranged in plates across the upper jaw of whales.

Depending on the species, a baleen plate can be 0.5 to 3.5 m (1.6 to 11.5 ft) long, and weigh up to 90 kg (200 lb). Its hairy fringes are called baleen hair or whalebone hair. They are also called baleen bristles, which in sei whales are highly calcified, with calcification functioning to increase their stiffness. Baleen plates are broader at the gumline (base). The plates have been compared to sieves or Venetian blinds.

A scrubber (German: Schrubber), is a type of wide brush with a long shaft used for cleaning hard floors or surfaces. Unlike a broom, which has soft bristles to sweep dirt away, a scrubber has hard bristles for brushing. It may therefore be used wet, with water or cleaning fluids. Around the head of the brush there may also be a removable floorcloth or mop, either soaked in water for cleaning or dry for wiping dry. However, these days other cleaning implements tend to be used for such purposes.

In North Germany and in sailor's language, a scrubber is also called a Leuwagen, hence in large firms or offices a cleaning party is sometimes jokingly called a Leuwagenballett ("scrubber ballet").

A wire brush is a tool consisting of a brush whose bristles are made of wire, most often steel wire. The steel used is generally a medium- to high-carbon variety and very hard and springy. Other wire brushes feature bristles made from brass or stainless steel, depending on application. Wires in a wire brush can be held together by epoxy, staples, or other binding. Wire brushes usually either have a handle of wood or plastic (for handheld use) or are formed into a wheel for use on angle grinders, bench grinders, pistol-grip drill motors, or other power tools.

In biology, an indumentum (Latin, literally: "garment") is a covering of trichomes (fine "hairs") on a plant or of bristles (rarely scales) of an insect.

Cyclothone is a genus containing 13 extant species of bioluminescent fish, commonly known as 'bristlemouths' or 'bristlefishes' due to their shared characteristic of sharp, bristle-like teeth. These fishes typically grow to around 1–3 inches (25–76 mm), though some can be larger. These deep-sea fish are most commonly found in the mesopelagic zone of the ocean, mostly at depths of over 300 meters (1,000 feet), and many species have bioluminescence.

Cyclothone is believed to be the most abundant fish genus on Earth, with estimates that there are up to a quadrillion individuals (10, or one million billion in the short scale) within the current global population. They are so abundant that they are also believed to be the most abundant genus of vertebrate on earth.

The thick-billed raven (Corvus crassirostris), a corvid from the Horn of Africa, shares with the common raven the distinction of being the largest bird in the corvid family. The thick-billed raven averages 64 cm (25 in) in length, with a range of 60 to 70 cm (24 to 28 in) and weighs approximately 1.15 kg (2.5 lb) in females and 1.5 kg (3.3 lb) in males on average. Its size is about the same as the largest subspecies of common raven (i.e. those from the Himalayas and Greenland/Canadian Northwest Atlantic) but some common raven subspecies are rather smaller and, going on average weights, the thick-billed raven is likely the heaviest extant passerine. The thick-billed raven is about 25% heavier on average than the Australasian superb lyrebird, which is sometimes erroneously titled the largest passerine.

It has a very large bill that is laterally compressed and is deeply curved in profile giving the bird a very distinctive appearance. This bill, the largest of any passerine at 8–9 cm (3.1–3.5 in) in length, is black with a white tip and has deep nasal grooves with only light nasal bristle covers. This raven has very short feathers on the head, throat and neck. The throat and upper breast have an oily brown gloss, while the rest of the bird is glossy black except for a distinctive white patch of feathers on the nape and onto the neck.