Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic.
Common meanings of diamond include:
1. A precious stone consisting of a clear and typically colorless crystalline form of pure carbon
2. A figure with four straight sides of equal length forming two opposite acute angles and two opposite obtuse angles
3. The area of a baseball field within the square formed by the four bases
4. A playing card of the suit bearing red figures of this shape
5. A tool with a small diamond for cutting glass