Seating Capacity
One critical area that defines the difference between the two is seating capacity. Couches are typically smaller, designed to seat two to three people. Sofas are larger than couches and are designed to accommodate four or more persons. It is very likely that you`ve also seen a two seater sofa, which is appropriately referred to as a loveseat. Loveseats are a smaller version of a standard sofa, designed to accommodate two people instead of four.
Functional Use
You probably didn`t know this, but couches are actually intended to be lied upon rather than sat on. Conversely, the sofa is designed for seating purposes. This is one of the reasons why genuine couches are armless. The functional use leads us to our next point; location.
Location
Sofas are commonly seen in the living room, family room, and other areas of the home. They are made to seat a large group of people and for this reason, are usually seen in larger areas of the home. Couches, on the other hand, are more commonly seen in intimate areas of the home. This can include informal areas that host cordial entertainment events for family and friends. This facilitates a more casual environment where laying down is to be expected.
Etymology and History
The word sofa originates from the Arabic word [suffah," which is used to describe a bench that has been covered with cushions and blankets. Not exactly the modern definition, right?
The word couch originates from the French word [couche" and is used to describe a piece of furniture with no arms. Sometimes a couch can include a single arm and still be classified as such, however, this falls within the gray area between the two styles. The couch is similarly related to the modern [chaise lounge" which is a bench for laying that does not have arms.