Real Dictionary

stone
A stone is a small hard ball of minerals and other substances which sometimes forms in a person's kidneys or gall bladder.
countable noun: A stone is a large piece of stone put somewhere in memory of a person or event, or as a religious symbol.
countable noun: A stone is a small piece of rock that is found on the ground.
countable noun: You can refer to a jewel as a stone.
variable noun: Stone is a hard solid substance found in the ground and often used for building houses.

Stone in American English
Edward Duˈrell (dəˈrɛl ) 1902-78; U.S. architect
the hard, solid, nonmetallic mineral matter of which rock is composed

stone in American Englishfor 6
noun: the hard substance, formed of mineral matter, of which rocks consist

stone- in American English
very, completely

stone- in British English
prefix: very; completely