The term 'PART OF A CHAIR' can be broken down into three crossword solutions: armrest (7 letters), backrest (8 letters), and SEAT (4 letters). An armrest is a support for the arm, typically found on either side of a chair. A backrest is a support for the back, usually found at the top of a chair. Finally, a SEAT is the part of the chair that one sits on. All three of these components are essential parts of a chair.