endonym Helvetii is mostly derived from a
Gaulish elu-, meaning "gain, prosperity" or "multitude", cognate with
Welsh elw and
Old Irish prefix il-, meaning "many" or "multiple" (from the
PIE root *pelh1u- "many").
 The second part of the name has sometimes been interpreted as *etu-, "terrain, grassland", thus interpreting the tribal name as "rich in land".
The earliest attestation of the name is found in a graffito on a vessel from
Mantua, dated to c. 300 BC.
 The inscription in
Etruscan letters reads eluveitie, which has been interpreted as the
Etruscan form of the Celtic elu̯eti̯os ("the Helvetian"), presumably referring to a man of Helvetian descent living in Mantua.
The name of the national personification of
Helvetia, and the country's
Neo-Latin name, Confoederatio Helvetica, are both derived from the name of the Helvetii.
51 Pegasi was named Helvetios after them.
 This was the first
main-sequence star found to have an
exoplanet orbiting it.