1. Soils of slight and recent development, common along rivers and flood plains.
2. Soils with little or no morphological development.
3. Soils which are very young and may be only years or decades old; however, in cold climates or other places where chemical weathering is slow, entisols may be much older.

Different subtypes are found in Labrador's glacial deposits, northern China's flood deposits, and the Kalahari's dune deposits in Africa.

Enttisols are divided into six suborders: Wassents, Aquents, Arents, Psamments, Fluvents, and Orthents; all of which are defined alphabetically in other locations of this unit.

4. From the U.S. Soil Taxonomy soil-order classification system.
5. Etymology: apparently from the ent in Latin recentem, "recent; lately done or made, new, fresh".