noun

1. a solidifying or being solidified
2. an act or instance of concretizing
3. a solidified mass; specif.,
   1. Geol. an inclusion in sedimentary rock, usually rounded and harder than the surrounding rock, resulting from the formation of succeeding layers of mineral matter about some nucleus, as a grain of sand
   2. Med. a solidified mass, usually inorganic, deposited in the body; calculus

Etymology: L concretio: see concrete