a hard solid mass formed by the local accumulation of matter, especially within the body or within a mass of sediment:nodular concretions of siderite growing within the sediments
[mass noun] the process by which matter forms into a concretion.
Derivatives
concretionary
adjective
Origin:
mid 16th century: from Latin concretio(n-), from concrescere 'grow together'
concretion in other Oxford dictionaries
Definition of concretion in the US English dictionary
