Banjo

The banjo is a four-, five- or (occasionally) six-stringed instrument with a thin membrane stretched over a frame or cavity as a resonator, called the head. The membrane, or head, is typically made of plastic, although animal skin is still occasionally but rarely used, and the frame is typically circular. Early forms of the instrument were fashioned by Africans in America, adapted from African instruments of similar design.

The banjo is frequently associated with country, folk, Irish traditional and bluegrass music. Historically, the banjo occupied a central place in African American traditional music, before becoming popular in the minstrel shows of the 19th century. The banjo, with the fiddle, is a mainstay of American old-time music. It is also very frequently used in Traditional Jazz.

History

There are several theories concerning the origin of the name banjo. It could have come from the Yoruba word or term "Bami jo" which means "dance for me". It may derive from the Kimbundu term mbanza. Some etymologists believe it comes from a dialectal pronunciation of the Portuguese "bandore" or from an early anglicisation of the Spanish word bandurria, though other research suggests that it may come from a West African term for a bamboo stick formerly used for the instrument's neck.

Banjo (wood lathe)

In the craft of woodturning, a banjo is a common term for a fixture on the wood lathe, mounted on the lathe's bed, for holding the toolrest. It allows for adjustment of the toolrest in various positions, by the lathe operator, making it possible to hold the turning tool in the most convenient position for removing material from the spinning wood. The chosen position of the fixture can be locked in place on the lathe's bed in various ways, the most common method being a lever at the forward end of the fixture which acts upon an eccentric shaft with an attached clamp to secure the fixture to the lathe's bed.

North American railroad signals

North American railroad signals generally fall into the category of multi-headed electrically lit units displaying speed-based or weak route signaling. Signals may be of the searchlight, color light, position light, or color position light types, each displaying a variety of aspects which inform the locomotive engineer of track conditions so that he or she may keep their train under control and able to stop short of any obstruction or dangerous condition.

There is no national standard or system for railroad signaling in North America. Individual railroad corporations are free to devise their own signaling systems as long as they uphold some basic regulated safety requirements. Due to the wave of mergers that have occurred since the 1960s it is not uncommon to see a single railroad operating many different types of signaling inherited from predecessor railroads. This variety can range from simple differences of hardware to completely different rules and aspects. While there has been some recent standardization within railroads in terms of hardware and rules, diversity remains the norm.