Pyura chilensis, called piure in Spanish and piür or piwü in Mapudungun, is a tunicate of the family Pyuridae. It was described in 1782 by Juan Ignacio Molina.

A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata. It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords. The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. They are the only chordates that have lost their myomeric segmentation, with the possible exception of the 'seriation of the gill slits'. However, doliolids still display segmentation of the muscle bands.