Vair, along with it's varients (no pun intended) counter-vair, vair-en-point, and vair-in-pale are among the common heraldic furs. Since it's almost impossible to describe vair at all, much less the variations, without pictures. (to come later) I'll stick to saying that it's a bunch of interlocking bell-shapes, colored blue and white ( azure and argent), unless other tinctures are named.
In heraldry, vair is a "fur", a tincture which is simultaneously a two-coloured field treatment. It is found in a variety of colours, and appears in different arrangements, each with its own name.