A Concretion

1. The process of aggregating or coalescing into a mass.
2. A solid, hard mass formed by a process of aggregation or coalescence.
3. (petrology) A rounded mass of a mineral, sometimes found in sedimentary rock or on the ocean floor.
4. The action of making something concrete or the result of such an action.

Usage notes

• Concretion and concretization are rough synonyms but are usually not used interchangeably. Concretion is more commonly used to refer to a physical object or to the physical process which creates it. Concretization is more commonly used to refer to a particular embodiment of a general concept or to the process which creates it.