mar·ble 
(märbəl)
(märbəl)n.
1.
a. A metamorphic rock formed by alteration of limestone or dolomite, often irregularly colored by impurities, and used especially in architecture and sculpture.
b. A piece of this rock.
c. A sculpture made from this rock.
2. Something resembling or suggesting metamorphic rock, as in being very hard, smooth, or cold: a heart of marble; a brow of marble.
3. Games
a. A small hard ball, usually of glass, used in children's games.
b. marbles (used with a sing. verb) Any of various games played with marbles.
4. marblesSlang Common sense; sanity: completely lost his marbles after the stock market crash.
5. Marbling.
tr.v. mar·bled, mar·bling, mar·bles
To mottle and streak (paper, for example) with colors and veins in imitation of marble.
adj.
1. Composed of metamorphic rock: a marble hearth.
2. Resembling metamorphic rock in consistency, texture, venation, color, or coldness.
[Middle English marbre, marble, from Old French marbre, from Latin marmor, from Greek marmaros, of unknown origin.]
marbly adj.