1. a. Concreted earthy or mineral matter; rock. b. Such concreted matter of a particular type. Often used in combination: sandstone; soapstone.
2. A small piece of rock.
3. Rock or a piece of rock shaped or finished for a particular purpose, especially: a. A piece of rock that is used in construction: a coping stone; a paving stone. b. A gravestone or tombstone. c. A grindstone, millstone, or whetstone. d. A milestone or boundary.
4. A gem or precious stone.
5. Something, such as a hailstone, resembling a stone in shape or hardness.
6. Botany. The hard covering enclosing the seed in certain fruits, such as the cherry, plum, or peach.
7. Pathology. A mineral concretion in an organ, such as the kidney or gallbladder, or other body part; a calculus.
8. plural stone Abbr. st. A unit of weight in Great Britain, 14 pounds (6.4 kilograms).
9. Printing. A table with a smooth surface on which page forms are composed.
Used as an intensive. Often used in combination: stone cold; standing stone still.