MATTRESS FIRM is a company that specializes in selling mattresses and bedding products. They offer a wide variety of mattress brands, including SERTA, which is a 5-letter word that can be found in the crossword puzzle. SERTA is a leading mattress manufacturer that has been providing quality sleep solutions for over 80 years. MATTRESS FIRM provides customers with a wide selection of mattresses from SERTA, as well as other top brands, to ensure they get the best sleep possible.