The term 'BIG BRAND OF ELEVATORS' can be summarized by the crossword solution OTIS, which is a four-letter word. OTIS is a world-renowned elevator and escalator company that has been in business since 1853. It is the world's leading manufacturer of elevators, escalators, and moving walkways, with products installed in many of the world's most iconic buildings. OTIS is known for its innovative technology and commitment to safety, making it one of the most trusted names in the industry.