The crossword solution for the term 'PILLOW's Center' is ELS, which stands for 'elastic loft system'. This is a type of technology used in pillows to provide support and comfort. It is made up of a combination of elastic foam and air-filled chambers that work together to provide cushioning and support. The elastic loft system helps to keep the PILLOW's center from flattening out over time, providing a more comfortable sleep experience.