Pronunciation: (sep-târ'ē-um), [key]
—pl. -tar•i•aPronunciation: (-târ'ē-u). [key] Geol.
a concretionary nodule or mass, usually of calcium carbonate or of argillaceous carbonate of iron, traversed within by a network of cracks filled with calcite and other minerals.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.