The "contact patch" refers to the area where a tire touches the ground. It is the small portion of the tire that is in contact with the road while driving. Full definition
They offer the largest contact patch of any production car built. (bestride.com)
Anything that increases the tire contact patch will increase the ability of the road to induce a torque on the wheel (and vice versa). (mechanics.stackexchange.com)
Overall, the wider tires offer a significantly larger contact patch than those of the regular 911 GT3. (cheersandgears.com)