The sloth's taxonomic suborder is Folivora, sometimes also called Phyllophaga (Owen, 1842) or Tardigrada (Latham and Davies, 1795). The first two names both mean "leaf-eaters"; derived from Latin and Greek, respectively. Names for the animals used by tribes in Ecuador include ritto, rit, and ridette, mostly forms of the word "sleep", "eat", and "dirty" from Tagaeri tribe of Huaorani.
The English word "sloth" (a derivative of the adjective "slow") is recorded as meaning "laziness", "indolence" from the twelfth century onwards, and is considered as one of the seven cardinal sins.[3] It was applied to the animal in the early seventeenth-century, as a calque of the Portuguese preguiça ("laziness").[4] The pronunciation is /ˈsloʊθ/ slohth or /ˈslɒθ/ sloth.