The term 'SEIZES FIRMLY' can be summarized by the crossword solution 'GRIPS', which is a five-letter word. To 'GRIP' something means to take hold of it firmly and securely, usually with one's hands. This term is often used in physical activities such as sports or martial arts, where an individual needs to have a strong GRIP on an object in order to control it. It can also be used figuratively to describe a person's mental or emotional hold on a situation.