couch，sofa，沙发到底应该怎么说？

最近找到一个很好的网站，对于区分一些傻傻分不清的单词很有帮助：
https://couch.askdefine.com/

提到沙发，脑子自然而然冒出来的单词就是sofa，毕竟这个外来词就是照着sofa翻译的。但是也经常听到一些人用couch这个词，那么它们有什么区别呢？参见askdefine的解释：
A couch is an upholstered item of furniture for the comfortable seating of <b>more than one person</b> and typically has an armrest on either side. Couches are usually to be found in the living room, den or the lounge. They are covered in a variety of textiles or in leather.
The most common types of couches are <b>the loveseat (or British two-seater), the settee (2.5 seats), and the sofa (3 seats)</b>. A sectional sofa (often just referred to as a "sectional") is formed from multiple sections (typically 2 to 4) and usually includes at least two pieces that join at an angle of 90 degrees or slightly great
![Uploading loveseat_077758.jpg . . .]
er.

重点看加粗部分，总结一下：

• loveseat (英国叫two-seater)：两人沙发

  
  
  loveseat.jpg

• settee：2.5座沙发

  
  
  settee.jpg
• sofa：三人沙发

sofa.jpg

看清楚，三人座的沙发才叫sofa哦！那么是不是说，couch才是沙发的统称？非也，上面粗体字说了，要可以坐1人以上才叫couch，也就是至少是两人沙发。一个人坐的沙发叫做armchair，就是下面这种：

armchair.jpg