Coleoptera ( /koʊliːˈɒptərə/) is an order of insects commonly called beetles. The word "coleoptera" is from the Greek κολεός, koleos, "sheath"; and πτερόν, pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms. About 40% of all described insect species are beetles (about 400,000 species), and new species are discovered frequently. Some estimates put the total number of species, described and undescribed, at as high as 100 million, but 1 million is a more accepted figure. The largest taxonomic family, the Curculionidae (the weevils or snout beetles), also belongs to this order.