The term 'BIG ELEVATOR MANUFACTURER' can be summarized by the crossword solution OTIS, which is a 4-letter word. OTIS is a company that has been in business since 1853 and is one of the world's leading elevator manufacturers. They specialize in the design, manufacture, installation, and service of elevators, escalators, and moving walkways. OTIS is known for its innovative products and services, and its commitment to safety and reliability.