The term 'hold firmly' can be expressed in a variety of ways, each of which is represented by one of the crossword solutions. RIVET (5 letters) is a fastener that is used to hold two or more objects together. GRASP (5 letters) is to take hold of something firmly with the hand. GRIP (4 letters) is to take hold of something firmly with the hand or fingers. CLUTCH (6 letters) is to take hold of something tightly and firmly. Enclasp (7 letters) is to clasp or embrace something firmly. CLAMP (5 letters) is to fasten or secure something firmly. Engrasp (7 letters) is to seize something firmly with the hand.