Zest

The grated colored outer peel of citrus fruit, which is used to add flavor. To create zest, choose the diagonal-hole side of a box grater (it will zest more cleanly than if you use the nail-hole side) and rub lightly to avoid getting the white pith, which is bitter. For broader strips of zest, use a swivel-blade peeler or a sharp knife to cut away the peel.