CATEGORY: geology DEFINITION: Aggregate(s) of particles that are spherical or polyhedral but porous.
CATEGORY: term DEFINITION: The dispersion of people, either forced or voluntary, from a central area of origin to many distant regions. In particular, the dispersion of Jews among the Gentiles after the Babylonian Exile or the aggregate of Jews or Jewish communities scattered in exile" outside Palestine or present-day Israel."
CATEGORY: term DEFINITION: The ethnic group, defined as a firm aggregate of people, historically established on a given territory, possessing in common relatively stable peculiarities of language and culture, and also recognizing their unity and difference as expressed in a self-appointed name (ethnonym).
CATEGORY: geology DEFINITION: An aggregate of landforms in a region; the collection of landforms particular to a region at a particular time.
CATEGORY: structure DEFINITION: A Roman construction technique of crushed brick set in mortar, a kind of waterproof plaster, used to seal walls and floors in bath complexes. The mix was essentially a lime mortar with an aggregate of coarse pieces of broken terra-cotta. This Latin technique term was used by Vitruvius c 30 BC.
CATEGORY: geology DEFINITION: Aggregates of soil or sediment particles.
CATEGORY: lithics DEFINITION: An aggregate of one or more minerals that can be defined by both physical properties and mineral content. The three forms are igneous, rock that has cooled from a molten state; sedimentary, rock that has formed through the accretion of sediments; and metamorphic, rock formed from preexisting rocks subjected to extreme heat, pressure, or chemical change.
CATEGORY: geology DEFINITION: Physical arrangement of sediment into peds (a natural soilaggregate) as the result of pedogenesis (reproduction by young or larval animals). Soil has a structure" on which its porosity-permeability depends. Soilstructure is built up by alternate moistening and drying and plant roots contribute greatly by opening pores between soil aggregates. The stability of aggregates increases with humus content especially humus that originates from grass vegetation."
SYNONYMS OR RELATED TERMS: boulder clay CATEGORY: geology DEFINITION: An aggregate of material -- unsorted soil consisting of sand, gravel, clay, and unsorted stones, and deposited directly by a glacier or ice sheet. All grades of particle size may be found. Till is sometimes called boulder clay because it is composed of clay, boulders of intermediate sizes, or a mixture of these. Ice does not sort the material it carries and the range of particle sizes, as well as the range of rock types, depends on the geology over which the ice-sheet or glacier has flowed. There are two types of till, basal and ablation. Basal till is that which was carried in the base of the glacier and commonly set under it. Ablation till is that which was carried on or near the surface of the glacier and came down as the glacier melted.
CATEGORY: term DEFINITION: An egalitarian society generally comprised of a centrally organized group of bands. Its kinship is more complex than that of the band, and its economy is often agricultural rather than foraging, though they also include nomadic pastoral groups whose economy is based on exploitation of livestock. Individual communities tend to be integrated into the larger society through kinship ties. Political dominance gained through achieved leadership. Tribes may be aggregated into higher-order clusters, called nations.