Fork

As a piece of cutlery or kitchenware, a fork is a tool consisting of a handle with several narrow tines on one end. The fork is a primarily Western utensil, whereas in East Asia chopsticks have been more prevalent. Today, forks are increasingly available throughout East Asia. The usually metal utensil is used to lift food to the mouth or to hold ingredients in place while they are being cut by a knife. Food can be lifted either by spearing it on the tines, or by holding it on top of the tines, which are often curved slightly. A fork is shaped in the form of a trident but curved at the joint of the handle to the points.

Early history of forks is obscure, as a kitchen and dining utensil it's generally believed to have originated in the Roman Empire, as proved by archaeological evidences. The personal table fork most likely originated in the Eastern Roman, or Byzantine, Empire. Its use spread to what is now the Middle East during the first millennium CE and then spread into southern Europe during the second millennium. It did not become common in northern Europe until the 18th century and was not common in North America until the 19th century.

Intersection (road)

An intersection is the junction at-grade (that is to say, on the same level) of two or more roads either meeting or crossing. An intersection may be three-way (a T junction or Y junction – the latter also known as a fork if approached from the stem of the Y), four-way (often in the form of a crossroads), or have five (a 5-points) or more arms. Busy intersections are often controlled by traffic lights and/or a roundabout.

This article primarily reflects practice in jurisdictions where vehicles are driven on the right. If not otherwise specified, "right" and "left" can be reversed to reflect jurisdictions where vehicles are driven on the left.

Types of intersections

Road segments

One way to classify intersections is by the number of road segments (arms) that are involved.

Fork (chess)

In chess, a fork is a tactic whereby a single piece makes two or more direct attacks simultaneously. Most commonly two pieces are threatened, which is also sometimes called a double attack. The attacker usually aims to gain material by capturing one of the opponent's pieces. The defender often finds it difficult to counter two or more threats in a single move. The attacking piece is called the forking piece; the pieces attacked are said to be forked. A piece that is defended can still said to be forked if the forking piece has a lower value.

Besides attacking pieces, a target of a fork can be a direct mating threat (for example, attacking an unprotected knight while simultaneously setting up a battery of queen and bishop to threaten mate). Or a target can be an implied threat (for example, a knight may attack an unprotected piece while simultaneously threaten to fork queen and rook).

Forks are often used as part of a combination which may involve other types of chess tactics as well.

Slug

Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word slug is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly sea slugs and semislugs (this is in contrast to the common name snail, which applies to gastropods that have a coiled shell large enough that the animal can fully retract its soft parts into the shell).

Various taxonomic families of land slugs form part of several quite different evolutionary lineages, which also include snails. Thus, the various families of slugs are not closely related, despite a superficial similarity in the overall body form. The shell-less condition has arisen many times independently during the evolutionary past, and thus the category "slug" is emphatically a polyphyletic one.

Taxonomy

Of the six orders of Pulmonata, two – the Onchidiacea and Soleolifera – solely comprise slugs. A third family, the Sigmurethra, contains various clades of snails, semi-slugs (i.e. snails whose shells are too small for them to retract fully into) and slugs. The taxonomy of this group is in the process of being revised in light of DNA sequencing. It appears that pulmonates are paraphyletic and basal to the opisthobranchs, which are a terminal branch of the tree. The family Ellobiidae are also polyphyletic.

Slug (typesetting)

In typesetting, a slug is a piece of lead or other type metal, in any of several specific word senses. In one sense, a slug is a piece of spacing material used to space paragraphs. In the era of commercial typesetting in metal type, they were usually manufactured in strips of 6-point lead. In another sense, a slug is one line of Linotype typeset matter, where each line corresponds to one piece of lead.

In modern typesetting programs such as Adobe InDesign, slugs hold printing information, customized color bar information, or displays other instructions and descriptions for other information in the document. Objects (including text frames) positioned in the slug area are printed but will disappear when the document is trimmed to its final page size.

Usage in web publishing

More recently this term is also used in web publishing to refer to short article labels that can be used as a part of an URL. Slugs are usually derived from article's title and are limited in length and the set of characters (to prevent percent-encoding, often only letters, numbers and hyphens are allowed).

Slug (railroad)

A railroad slug is an accessory to a diesel-electric locomotive. It has trucks with traction motors but, unlike a B unit, is unable to move about under its own power, as it does not contain a prime mover to produce electricity, nor is there a cab for an operator. Instead, it is connected to a locomotive, called the mother, which provides the needed electrical power to operate the traction motors, and the motor controls.

Basic principles

A slug is used to increase adhesive weight, allowing full power to be applied at a lower speed, thus allowing a higher maximum tractive effort. They are often used in low-speed operations such as switching operations in yards. At low speeds, a diesel-electric locomotive prime mover is capable of producing more electricity than its traction motors can use effectively. Extra power would simply cause the wheels to slip and possibly overheat the traction motors. A slug increases the number of traction motors available to the locomotive, increasing both the pulling and braking power. In addition the load on each traction motor is reduced, which helps prevent overheating from excess current. Slugs typically carry ballast to increase their weight and improve traction. Large blocks of concrete are frequently used for this purpose, substituting for the weight of the now-absent prime mover.