Orthents are soils defined in USDA soil taxonomy as entisols that lack horizon development due to either steep slopes or parent materials that contain no permanent weatherable minerals (such as ironstone).
Typically, Orthents are exceedingly shallow soils. They are often referred to as skeletal soils or, in the United Nations FAO soil classification, as lithosols.
Entisols are soils, as defined under USDA soil taxonomy, that do not show any profile development other than an A-horizon (or “A” horizon). Entisols have no diagnostic horizons, and are unaltered from their parent material, which could be unconsolidated sediment, or rock. Entisols are the most common soils, occupying about 16% of the global ice-free land area.
Because of the diversity of their properties, suborders of entisols form individual Reference Soil Groups in the World Reference Base for Soil Resources (WRB): psamments correlate with arenosols, and fluvents with fluvisols. Many orthents belong to regosols or leptosols. Most wassents and aquic subgroups of other suborders belong to the gleysols.