Pronunciation: 'skw&r(-&)l, 'skw&-r&l, chiefly British 'skwir-&l
Function: noun
Inflected Form(s): plural squirrels also squirrel
Etymology: Middle English squirel, from Middle French esquireul, from (assumed) Vulgar Latin scuriolus, diminutive of scurius, alteration of Latin sciurus, from Greek skiouros, probably from skia shadow + oura tail -- more at SHINE, ASS
1 : any of various small or medium-sized rodents (family Sciuridae, the squirrel family): as a : any of numerous New or Old World arboreal forms having a long bushy tail and strong hind legs b : GROUND SQUIRREL
2 : the fur of a squirrel

From the Merriam-Webster Online Dictionary