a crossing is a new grape variety that was created by the cross pollination of two different varieties of the same species. syrah is a crossing of two french "vitis vinifera" species, dureza from the ardèche and mondeuse blanche from savoie. theoretically, every seedling (also known as a selfling), even if its pollinated by a member of the same grape variety (i.e. such as two merlot vines), is a crossing as any vine that results from the seed being planted will be a different grape variety distinct from either parent.