Definition of "Diamond" :

noun: the baseball playing field

noun: the area of a baseball field that is enclosed by 3 bases and home plate

noun: a playing card in the minor suit that has one or more red rhombuses on it

"He led a small diamond."

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

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

noun: very hard native crystalline carbon valued as a gem