There are many potential definitions for soil. For instance, the Soil Science Society of America (https://www.soils.org/ sssagloss/) defines soil as follows:
soil (i) The unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants. (ii) The unconsolidated mineral or organic matter on the surface of the earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time. A product-soil differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.
A key part of the definition views soil as a product of soil formation processes. Also key to understanding soil in this way is to think of the 'life' of soil similar to a human lifetime. Soils are created by the action of soil-forming processes on a material that is not initially soil (i.e., rock). Soils have various stages of development sometimes called 'infant', 'young', 'mature', and 'senile' as soil minerals change, elements are added and removed, and the processes of soil formation under geologically stable conditions can ultimately result in deposits of highly resistant minerals not readily subject to further weathering. The process of soil formation can be reset by removal or covering of the soil profile (i.e., erosion, glaciation, flood deposits, volcanic eruptions). The study of ancient soil profiles, including sometimes the human remains in them, is an important part of archeology. Deep soil layers typically change very slowly.
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