diamond

(noun) a transparent piece of diamond that has been cut and polished and is valued as a precious gem.

(noun) very hard native crystalline carbon valued as a gem. Synonyms: adamant.

(noun) a parallelogram with four equal sides; an oblique-angled equilateral parallelogram. Synonyms: rhombus, rhomb.

(noun) a playing card in the minor suit that has one or more red rhombuses on it. Examples: "He led a small diamond." "Diamonds were trumps."

(noun) the area of a baseball field that is enclosed by 3 bases and home plate. Synonyms: baseball diamond, infield.

(noun) the baseball playing field. Synonyms: ball field, baseball field.