EARTH SCIENCE > LAND SURFACE > SOILS > SOIL STRUCTURE
The combination or arrangement of primary soil particles into secondary units or peds. These secondary units may be, but usually are not, arranged in the profile in such a manner as to give a distinctive characteristic
pattern. The secondary units are characterized and classified on the basis of size, shape, and degree of distinctness into classes, types, and grades, respectively.
The Nature and Properties of Soils, Prentice Hall, 1996.