Any one of numerous species of small rodents belonging to the genus Sciurus and several allied genera of the family Sciuridæ. Squirrels generally have a bushy tail, large erect ears, and strong hind legs. They are commonly arboreal in their habits, but many species live in burrows.
- Any of various arboreal rodents of the genus Sciurus and related genera of the family Sciuridae, having a long flexible bushy tail and including the fox squirrel, gray squirrel, and red squirrel. Also called tree squirrel.
- Any of various other rodents of the family Sciuridae, as the ground squirrel or the flying squirrel.
- The fur of one of these rodents.
- To hide or store: squirreled away her money.