Gravel/ˈɡrævl/ Definition 1 of 3Pro Tip 1/3Material Use Gravel refers to a construction material made from small rocks. Load a truck with gravel for the construction site. Pro Tip 2/3Outdoor Surface Gravel is commonly used outdoors to cover paths and driveways. Her bike kicked up gravel on the path. Pro Tip 3/3Not Smooth A gravel surface is rough and can be unstable to walk or drive on. Walking on gravel can be tricky due to the uneven surface.