Tire width refers to the measurement of a tire's cross-section from sidewall to sidewall. It is typically expressed in millimeters and is an important factor in determining a vehicle's handling, traction, and overall performance. Wider tires can provide better grip on the road, while narrower tires may improve fuel efficiency. The width of a tire is just one aspect of its overall size, which also includes aspects like aspect ratio and diameter. When selecting tires, it's essential to consider how the width will affect the vehicle's suspension, steering, and braking capabilities, as well as compatibility with the wheel size.