The word gaucho could be described as a loose equivalent to the North American "cowboy" (vaquero, in Spanish). Like the North American word cowboy, Venezuelan or Colombian llanero, or Chilean huaso, or the Mexican charro, the term often connotes the 19th century more than the present day; then gauchos made up the majority of the rural population, herding cattle on the vast estancias, and practising hunting as their main economic activities. The word "gaucho" is sometimes used to refer to chimichurri, a steak sauce common to Argentina.

There are several conflicting hypotheses concerning the origin of the term. It may derive from the Mapuche cauchu ("vagabond") or from the Quechua huachu ("orphan"), which gives also a different word in Spanish "guacho". The first recorded uses of the term date from around the time of Argentine independence in 1816.

Cattle were brought to the Pampas from Paraguay in 1580, by the colonial expedition of Juan de Garay. In the 18th century, the gauderios, who lived by hunting wild cattle, were recorded, most famously by the travel writer Alonso Carrió de la Vandera, when he passed through what is now northern Argentina. Commercial cattle ranching began in the second half of the 18th century.

Gauchos were generally nomadic, and lived in the Pampas, the plain that extends north from Patagonia, bounded on the west by the Andes and extending on the east to Uruguay and the Brazilian state of Rio Grande do Sul. These nomadic riders lived by hunting wild cattle. Most gauchos were of Spanish and/or Portuguese and/or Amerindian (native American) ancestry. There are also gauchos of largely African or part African ancestry as well.

An inconclusive genetic study conducted by FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) in 2007 detected a Amerindian with a, perhaps, stronger Spanish than Portuguese admixture in Brazilian gaúchos. A small African admixture was also found. The area that is Rio Grande do Sul belonged to the Spanish Crown for over two centuries before it became a Portuguese possession in 1750 (Treaty of Madrid)[clarification needed]. The results of the study were not conclusive, and raised questions that will require further attention. The study clearly showed that their MtDNA has much stronger affinities with Amerindian MtDNA in Argentina and Uruguay than with Amerindian MtDNA from other parts of Brazil and suggests that this is probably due to genetic ancestry from the now extinct Pampean Indians (Charrúa, Minuano).

Some gauchos were recorded as being in the Falkland Islands, and have left a few Spanish words in the local dialect e.g. camp from campo.

The gaucho plays an important symbolic role in the nationalist feelings of this region, especially that of Argentina and Uruguay. The epic poem Martín Fierro by José Hernández used the gaucho as a symbol against corruption and of Argentine national tradition, pitted against Europeanising tendencies. Martín Fierro, the hero of the poem, is drafted into the Argentine military for a border war, deserts, and becomes an outlaw and fugitive. The image of the free gaucho is often contrasted to the slaves who worked the northern Brazilian lands. Further literary descriptions are found in Ricardo Güiraldes' Don Segundo Sombra.

Like the North American cowboys[citation needed], gauchos were generally reputed to be strong, honest, silent types, but proud and capable of violence when provoked. The gaucho tendency to violence over petty matters is also recognized as a typical trait. Gauchos' use of the famous "facón" (large knife generally tucked into the rear of the gaucho sash) is legendary, often associated with considerable bloodletting. Historically, the facón was typically the only eating instrument that a gaucho carried.

There is, perhaps, more of an air of melancholy about the classic gaucho than the classic cowboy[citation needed].

Also like the cowboy[citation needed], the gauchos were and still are proud and great horseriders. Typically, a gaucho's horse constituted most of what he owned in the world. During the wars of the 19th century in the Southern Cone, the cavalries on all sides were composed almost entirely of gauchos. In Argentina, gaucho armies such as that of Martín Miguel de Güemes, slowed Spanish advances. Furthermore, many caudillos relied on gaucho armies to control the Argentine provinces.