Land use
What an area of land is actually used for, such as housing, industry, farmland or recreation. The basis of most planning regulation.
Land use describes what an area of land is used for: housing, retail, industry, farmland, forest, transport infrastructure, recreation. It is one of the most fundamental layers in planning, because almost every regulation and almost every plan is expressed in its terms.
Land use is not the same as land cover, although the two are often confused. Land cover is what physically covers the surface, which is what satellite imagery sees: grass, asphalt, trees, water. Land use is the human purpose. A grass surface can be a park, a sports field, a road verge or a set aside development site, and land cover cannot tell them apart.
The distinction matters for analysis. If you are mapping how much green space a city has, land cover will give you a number that includes traffic islands and private lawns. If you are mapping green space people can use, you need land use, and usually a further judgement about which categories count.
Land use also decides accessibility before any transport decision is made, because it fixes where the destinations are and how many people live near them.