The key difference is their shape. A sofa is a single, straight piece of furniture with a set number of seats, typically designed for compact or straightforward seating arrangements. A sectional, on the other hand, consists of multiple connected pieces arranged in an L or U shape, offering more seating and versatility for larger spaces.
While sectionals provide more seating and are ideal for maximizing space in larger living rooms, they usually come in pre-defined configurations that cannot be easily rearranged. For those seeking even more flexibility, modular sectionals allow for reconfiguring the individual sections to suit different room layouts or seating needs.