What is the meaning of diamond?

noun

• A transparent piece of diamond that has been cut and polished and is valued as a precious gem.
• Very hard native crystalline carbon valued as a gem.
  • synonyms: adamant
• A parallelogram with four equal sides; an oblique-angled equilateral parallelogram.
  • synonyms: rhombus, rhomb
• A playing card in the minor suit that has one or more red rhombuses on it.
  • usage: "he led a small diamond"; "diamonds were trumps"
• The area of a baseball field that is enclosed by 3 bases and home plate.
  • synonyms: baseball diamond, infield
• The baseball playing field.
  • synonyms: ball field, baseball field