Search: couch vs sofa
Why: I never used to say "sofa," but now sometimes I do. I also sometimes say "soda," but just as a joke.
Answer: A couch is the armless variety of furniture that one would have seen in the Victorian period, as in "fainting couch." It comes from the French coucher, "to lie down."
Sofa has this etymology:
1625, "raised section of a floor, covered with carpets and cushions," from Turk. sofa, from Ar. suffah "bench." Meaning "long stuffed seat for reclining" is recorded from 1717.or
Turkish, from Arabic suffa, carpet, divan, from Aramaic sippa, absolute form of sippeta, mator "someplace meant for reclining or sitting, but not laying."
The More You Know: Whatever, I lay on my csooufcah all the time. I have half a mind to lay on it right now.