The Collaborative International Dictionary of English v.0.48:
Agouti \A*gou"ti\, Agouty \A*gou"ty\ ([.a]*g[=oo]"t[i^]), n. [F.
agouti, acouti, Sp. aguti, fr. native name.] (Zool.)
1. A rodent of the genus Dasyprocta, about the size of a
rabbit, peculiar to South America and the West Indies. The
most common species is the Dasyprocta agouti.
2. the color of the agouti, a grayish-brown of grizzled
texture; -- used especially to describe the color of the
fur of a strain of mice. Also used attributively.