The strongest linguistic argument comes from the Mapuche people, the indigenous group that fiercely resisted the Inca and later the Spanish. Their language, Mapudungun, contains the word chilli (sometimes written trile or chile ), which can mean "where the land sinks down," "deep point," or "the end of the world."

Geographically, this makes perfect sense. The coastal valleys of central Chile (the Mapuche heartland) are "deep" in two ways: they are deep green with vegetation, and they are geologically deep, as the Andes rise sharply from the Pacific trench. Some linguists suggest that the Incas, who could not conquer the Mapuche, adopted the name Chile from the very people who lived there, and the Spanish later inherited it.

While no single theory has been proven 100%, the most accepted by modern Chilean historians is the ( chilli = "where the land is deep"). It acknowledges the indigenous people who lived there and accurately describes the unique geography of deep valleys and deep roots.

Antes de la llegada de los españoles, el Imperio Inca ya tenía conocimiento de estas tierras. Los cronistas españoles, como el Inca Garcilaso de la Vega, señalaron que los incas llamaban Chilli a los habitantes del extremo sur de su imperio (o más allá de él).

For a country as geographically distinct as Chile—a slender ribbon of land squeezed between the Pacific Ocean and the Andes Mountains—the origin of its name is surprisingly mysterious. Unlike "Argentina" (from the Latin for silver) or "Colombia" (after Christopher Columbus), the etymology of the word Chile remains an open debate among historians and linguists. There is no definitive record from Spanish conquistadors explaining why they chose the name, leaving us with four compelling theories.