stone (countable and uncountable, plural stones or (as unit of mass) stone)

(uncountable) A hard earthen substance that can form large rocks.
A small piece of stone, a pebble.
A gemstone, a jewel, especially a diamond.
(Britain) A unit of mass equal to 14 pounds (≈6.3503 kilograms), formerly used for various commodities (wool, cheese, etc.), but now principally used for personal weight.
(botany) The central part of some fruits, particularly drupes; consisting of the seed and a hard endocarp layer.
a peach stone
(medicine) A hard, stone-like deposit.
Synonym: calculus
(board games) A playing piece made of any hard material, used in various board games such as backgammon and go.
A dull light grey or beige, like that of some stones.
(curling) A 42-pound, precisely shaped piece of granite with a handle attached, which is bowled down the ice.
A monument to the dead; a gravestone or tombstone.
(obsolete) A mirror, or its glass.
(obsolete) A testicle.
(printing, historical) A stand or table with a smooth, flat top of stone, commonly marble, on which to arrange the pages of a book, newspaper, etc. before printing.
Synonym: imposing stone