A junction, when discussed in the context of transport

Transport

Transport or transportation is the movement of people, cattle, animals and goods from one location to another. Modes of transport include air, rail, road, water, cable, pipeline, and space. The field can be divided into infrastructure, vehicles, and operations...

, is a location where traffic

Traffic

Traffic on roads may consist of pedestrians, ridden or herded animals, vehicles, streetcars and other conveyances, either singly or together, while using the public way for purposes of travel...

 can change between different routes, directions, or sometimes modes, of travel.

Historical significance

Historically, many cities and market town

Market town

Market town or market right is a legal term, originating in the medieval period, for a European settlement that has the right to host markets, distinguishing it from a village and city...

s developed wherever there was a junction. The intersection of two or more routes offered opportunities for rest or trade for travelers and merchant

Merchant

A merchant is a businessperson who trades in commodities that were produced by others, in order to earn a profit.Merchants can be one of two types:# A wholesale merchant operates in the chain between producer and retail merchant...

s. Towns sprang up to accommodate this; the first such in Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 were probably at intersections of the Roman road

Roman road

The Roman roads were a vital part of the development of the Roman state, from about 500 BC through the expansion during the Roman Republic and the Roman Empire. Roman roads enabled the Romans to move armies and trade goods and to communicate. The Roman road system spanned more than 400,000 km...

s.

A similar effect came with the growth of rail transport

Rail transport

Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...

; so-called railway town

Railway town

A railway town is a settlement that originated or was greatly developed because of a railway station or junction at its site.In Victorian Britain, the spread of railways greatly affected the fate of many small towns...

s grew up near major railway junctions

Junction (rail)

A junction, in the context of rail transport, is a place at which two or more rail routes converge or diverge.This implies a physical connection between the tracks of the two routes , 'points' and signalling.one or two tracks each meet at a junction, a fairly simple layout of tracks suffices to...

 - originally to accommodate railway workers, but expanding into fully functioning settlements over time.

Junctions for specific transport modes

See main articles: Junction (road)

Junction (road)

A road junction is a location where vehicular traffic going in different directions can proceed in a controlled manner designed to minimize accidents. In some cases, vehicles can change between different routes or directions of travel.-Origins:...

 and Junction (rail)

Junction (rail)

A junction, in the context of rail transport, is a place at which two or more rail routes converge or diverge.This implies a physical connection between the tracks of the two routes , 'points' and signalling.one or two tracks each meet at a junction, a fairly simple layout of tracks suffices to...

.

There are many types of different junction for road transport

Road transport

Road transport or road transportation is transport on roads of passengers or goods. A hybrid of road transport and ship transport is the historic horse-drawn boat.-History:...

 and rail transport

Rail transport

Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...

 (including metro

Rapid transit

A rapid transit, underground, subway, elevated railway, metro or metropolitan railway system is an electric passenger railway in an urban area with a high capacity and frequency, and grade separation from other traffic. Rapid transit systems are typically located either in underground tunnels or on...

 and rapid transit

Rapid transit

A rapid transit, underground, subway, elevated railway, metro or metropolitan railway system is an electric passenger railway in an urban area with a high capacity and frequency, and grade separation from other traffic. Rapid transit systems are typically located either in underground tunnels or on...

 systems). If many of these are contained in a small area, and where passengers can change from one transport mode to the other in them, it is said to be a transport hub.

The word "junction"

The word "junction" derives from Latin iunctus, past participle of iungere, to join. The word "junction" in this context may also refer to:

• The general locality of a given interchange
• A specific interchange on a major road, e.g. motorway. This it the common use in the United Kingdom
  United Kingdom
  The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
  
  . For example, Milton Keynes
  Milton Keynes
  Milton Keynes , sometimes abbreviated MK, is a large town in Buckinghamshire, in the south east of England, about north-west of London. It is the administrative centre of the Borough of Milton Keynes...
  
   is said to be "off junction 13" of the M1
  M1 motorway
  The M1 is a north–south motorway in England primarily connecting London to Leeds, where it joins the A1 near Aberford. While the M1 is considered to be the first inter-urban motorway to be completed in the United Kingdom, the first road to be built to motorway standard in the country was the...
  
  .