The term 'set firmly' can be represented by four different crossword solutions: EMBED, IMBED, PLANT, and POSIT. EMBED means to fix something deeply and firmly in a surrounding mass. IMBED is a synonym of EMBED, meaning to fix something firmly in a surrounding mass. PLANT is to set or place firmly in the ground or other surface. POSIT is to set forth or assume as a fact. All four of these words refer to the idea of setting something firmly in place.