noun
a person who is not the main partner in a romantic or sexual relationship, but who is involved with one of the partners in that relationship
-
The jeweler showed me a beautiful sidepiece to complement the main diamond in the ring.
-
I love my new sidepiece necklace, it adds a pop of color to my outfit.
-
Check out my new sidepiece, she's a total dime.
-
In the game of chess, the queen is considered the most powerful sidepiece.