What does "diamond" mean?

Additional senses

1. 2.One of a suit of playing cards, stamped with the figure of a diamond.
2. 3.(Arch.) A pointed projection, like a four-sided pyramid, used for ornament in lines or groups.
3. 4.(Baseball) The infield; the square space, 90 feet on a side, having the bases at its angles.
4. 5.(Print.) The smallest kind of type in English printing, except that called brilliant, which is seldom seen. Note: * This line is printed in the type called Diamond. Black diamond, coal; (Min.) See Carbonado. -- Bristol diamond. See Bristol stone, under Bristol. -- Diamond beetle (Zoöl.), a large South American weevil (Entimus imperialis), remarkable for its splendid luster and colors, due to minute brilliant scales. -- Diamond bird (Zoöl.), a small Australian bird (Pardalotus punctatus, family Ampelidæ.). It is black, with white spots. -- Diamond drill (Engin.), a rod or tube the end of which is set with black diamonds; -- used for perforating hard substances, esp. for boring in rock. -- Diamond finch (Zoöl.), a small Australian sparrow, often kept in a cage. Its sides are black, with conspicuous white spots, and the rump is bright carmine. -- Diamond groove (Iron Working), a groove of V-section in a roll. -- Diamond mortar (Chem.), a small steel mortar used for pulverizing hard substances. -- Diamond-point tool, a cutting tool whose point is diamond-shaped. -- Diamond snake (Zoöl.), a harmless snake of Australia (Morelia spilotes); the carpet snake. -- Glazier's diamond, a small diamond set in a glazier's tool, for cutting glass.
5. 6.Resembling a diamond; made of, or abounding in, diamonds; as, a diamond chain; a diamond field.