- A precious stone or gem excelling in brilliancy and beautiful play of prismatic colors, and remarkable for extreme hardness.
- A geometrical figure, consisting of four equal straight lines, and having two of the interior angles acute and two obtuse; a rhombus; a lozenge.
- One of a suit of playing cards, stamped with the figure of a diamond.
- [Arch] A pointed projection, like a four-sided pyramid, used for ornament in lines or groups.
- [Baseball] The infield; the square space, 90 feet on a side, having the bases at its angles.
- [Print] The smallest kind of type in English printing, except that called brilliant, which is seldom seen.
Note: ☞ The diamond is native carbon in isometric crystals, often octahedrons with rounded edges. It is usually colorless, but some are yellow, green, blue, and even black. It is the hardest substance known. The diamond as found in nature (called a rough diamond) is cut, for use in jewelry, into various forms with many reflecting faces, or facets, by which its brilliancy is much increased. See Brilliant Rose. Diamonds are said to be of the first water when very transparent, and of the second or third water as the transparency decreases.
Note: ☞ This line is printed in the type called Diamond.
Etymology: OE. diamaund diamaunt, F. diamant, corrupted, fr. L. adamas, the hardest iron, steel, diamond, Gr. �. Perh. the corruption is due to the influence of Gr. � transparent. See Adamant Tame