Weathering is the adjustment of rocks to new environmental conditions
Many of the rocks comprising the continental and oceanic crust have been formed under conditions which are very different from those which exist at the Earth's surface. Typically rocks in the crust will have been formed at high temperatures and pressures, often in the absence of air or water. On the Earth's surface temperatures and pressures are lower, and both air and water may be present. Weathering is the adjustment of rocks to these new and different conditions. There are both physical and chemical weathering processes.
Define weathering.