1. (

• diamond

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

2. (

• diamond ,
• adamant

) very hard native crystalline carbon valued as a gem ;

3. (

• rhombus ,
• rhomb ,
• diamond

) a parallelogram with four equal sides; an oblique-angled equilateral parallelogram ;

4. (

• diamond ,

) a playing card in the minor suit that has one or more red rhombuses on it; "he led a small diamond"; "diamonds were trumps" ;

5. (

• baseball_diamond ,
• diamond ,
• infield

) the area of a baseball field that is enclosed by 3 bases and home plate ;

6. (

• ball_field ,
• baseball_field ,
• diamond ,

) the baseball playing field ;