Taupe is often mistaken for other shades of brown. A true taupe has no visible red undertone. It is a cool brown - leaning a little to the blue or lavender side of brown without the traces of yellow or orange you will find in a warm brown or a chocolate.
It is usually grayed down a little - like a Weimaraner. In fact as dogs go, Weims are true taupe - even referred to at times as gray ghosts because of their taupe hues and light eyes
Throw into the mix lighting, undertones and the fact that the color you see on your computer screen can be completely different than the one you bring home...