Facilitated by advanced sailing and navigational skills, and characterised by the longship, Viking activities at times also extended into the Mediterranean littoral, North Africa, the Middle East and Central Asia. Following extended phases of (primarily sea- or river-borne) exploration, expansion and settlement, Viking (Norse) communities and polities were established in diverse areas of north-western Europe, European Russia, the North Atlantic islands and as far as the north-eastern coast of North America. This period of expansion witnessed the wider dissemination of Norse culture, while simultaneously introducing strong foreign cultural influences into Scandinavia itself, with profound developmental implications in both directions.
Popular, modern conceptions of the Vikings—the term frequently applied casually to their modern descendants and the inhabitants of modern Scandinavia—often strongly differ from the complex picture that emerges from archaeology and historical sources. A romanticised picture of Vikings as noble savages began to emerge in the 18th century; this developed and became widely propagated during the 19th-century Viking revival. Perceived views of the Vikings as alternatively violent, piratical heathens or as intrepid adventurers owe much to conflicting varieties of the modern Viking myth that had taken shape by the early 20th century. Current popular representations of the Vikings are typically based on cultural clichés and stereotypes, complicating modern appreciation of the Viking legacy. These representations are not always accurate – for example, there is no evidence that they wore horned helmets.
One etymology derives víking from the feminine vík, meaning "creek, inlet, small bay". Various theories have been offered that the word viking may be derived from the name of the historical Norwegian district of Viken (or Víkin in Old Norse), meaning "a person from Viken". According to this theory, the word simply described persons from this area, and it is only in the last few centuries that it has taken on the broader sense of early medieval Scandinavians in general. However, there are a few major problems with this theory. People from the Viken area were not called 'Viking' in Old Norse manuscripts, but are referred to as víkverir (Modern Norwegian: vikvær), 'Vík dwellers'. In addition, that explanation could only explain the masculine (Old Scandinavian víkingr) and ignore the feminine (Old Norse víking), which is a serious problem because the masculine is easily derived from the feminine but hardly vice versa. The form also occurs as a personal name on some Swedish runestones. There is little indication of any negative connotation in the term before the end of the Viking Age.
Another etymology (supported by, among others, the recognised etymologist Anatoly Liberman) derives Viking from the same root as Old Norse vika, f. ‘sea mile’, originally ‘the distance between two shifts of rowers’, from the root *weik or *wîk, as in the Proto-Germanic verb *wîkan, ‘to recede’. This is found in the Proto-Nordic verb *wikan, ‘to turn’, similar to Old Icelandic víkja (ýkva, víkva) ‘to move, to turn’, with well-attested nautical usages. Linguistically, this theory is better attested, and the term most likely predates the use of the sail by the Germanic peoples of North-Western Europe, because the Old Frisian spelling shows that the word was pronounced with a palatal k and thus in all probability existed in North-Western Germanic before that palatalisation happened, that is, in the 5th century or before (in the western branch). In that case, the idea behind it seems to be that the tired rower moves aside for the rested rower on the thwart when he relieves him. The Old Norse feminine víking (as in the phrase fara í víking) may originally have been a sea journey characterised by the shifting of rowers, i.e. a long-distance sea journey, because in the pre-sail era, the shifting of rowers would distinguish long-distance sea journeys. A víkingr (the masculine) would then originally have been a participant on a sea journey characterised by the shifting of rowers. In that case, the word Viking was not originally connected to Scandinavian seafarers but assumed this meaning when the Scandinavians begun to dominate the seas.
In Old English, the word wicing appears first in the Anglo-Saxon poem, Widsith, which probably dates from the 9th century. In Old English, and in the history of the archbishops of Hamburg-Bremen written by Adam of Bremen in about 1070, the term generally referred to Scandinavian pirates or raiders. As in the Old Norse usages, the term is not employed as a name for any people or culture in general. The word does not occur in any preserved Middle English texts. One theory made by the Icelander Örnolfur Kristjansson is that the key to the origins of the word is "wicinga cynn" in Widsith, referring to the people or the race living in Jórvík (York, in the ninth century under control by Norsemen), Jór-Wicings. The word Viking was introduced into Modern English during the 18th-century Viking revival, at which point it acquired romanticised heroic overtones of "barbarian warrior" or noble savage. During the 20th century, the meaning of the term was expanded to refer not only to seaborne raiders from Scandinavia and other places settled by them (like Iceland and the Faroe Islands), but secondarily to any member of the culture that produced said raiders during the period from the late 8th to the mid-11th centuries, or more loosely from about 700 to as late as about 1100. As an adjective, the word is used to refer to ideas, phenomena, or artefacts connected with those people and their cultural life, producing expressions like Viking age, Viking culture, Viking art, Viking religion, Viking ship and so on.