From Biology-Online Dictionary | Biology-Online Dictionary


1. (Science: chemistry) The act or process of making or becoming solid.

2. (Science: ecology) a localised concentration of chemical compounds, (for example, calcium carbonate and iron oxide) in the form of a grain or nodule of varying size, shape, hardness and colour, concretions of significance in hydric soils are usually iron oxides and manganese oxides occurring at or near the soil surface, which have developed under conditions of fluctuating water tables.