any of numerous species of tree-dwelling rodent withs that have a long bushy tail and strong hind legs, that feeds and feed chiefly on nuts and seeds: genus Sciurus and other genera
used in the names of other members of the family Sciuridae, e.g. ground squirrel
the fur of any of these animals
informal a person who hoards things, from the squirrel's proverbial habit of hoarding nuts
[Middle English via Old French esquireul, ultimately from Greek skiouros squirrel, from skia shadow + oura tail]