The term 'BIGGEST PART' can be represented by three different crossword solutions: LEAD (4 letters), LEADROLE (8 letters), and LIONSSHARE (10 letters). LEAD is a verb meaning to guide or direct, and it can also refer to a position of authority. LEADROLE is a noun that refers to the most important role in a production or project. Finally, LIONSSHARE is an idiom that means the largest portion or majority of something.