The term 'PART OF A BLACK SUIT' can be represented by two crossword solutions: SPADE (5 letters) and FIVEOFCLUBS (11 letters). SPADE is a tool used for digging, but it is also the name of one of the four suits in a deck of playing cards. The other three suits are Hearts, Diamonds, and Clubs. FIVEOFCLUBS is a card from the Clubs suit, specifically the five of clubs. All four suits in a deck of playing cards are typically black, so both SPADE and FIVEOFCLUBS can be considered part of a black suit.