The Chilean recluse spider is a venomous spider

Spider

Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...

, Loxosceles laeta, of the family Sicariidae

Sicariidae

Sicariidae is a family of six-eyed venomous spiders known for their necrotic bites. The members of this family are haplogyne by definition . The family consists of two genera, Loxosceles and Sicarius, and contains about 120 species...

 (formerly of the family Loxoscelidae). In Spanish, it (and other South American recluse spiders) is known as , or "corner spider"; in Portuguese

Brazilian Portuguese

Brazilian Portuguese is a group of Portuguese dialects written and spoken by most of the 190 million inhabitants of Brazil and by a few million Brazilian emigrants, mainly in the United States, United Kingdom, Portugal, Canada, Japan and Paraguay....

, as or "brown spider". This spider is considered by many to be the most dangerous of the recluse spider

Recluse spider

The recluse spiders or brown spiders , also known as fiddle-back, violin spiders or reapers, are a venomous genus of spiders known for their necrotic bite, which sometimes produces a characteristic set of symptoms known as Loxoscelism...

s, and its bite is known to frequently result in severe systemic reactions, including death.
The Chilean recluse is one of the larger species of recluse spiders, generally ranging from 8–40 mm in size (including legs).