Where, when and what is the word 圆舞 used for? I've heard people call Waltz (music) either 华尔兹 or 圆舞曲, but I've only heard people call Waltz (dance) 华尔兹, never 圆舞.

According to Baidu, 圆舞 does have a meaning of Waltz (dance). It has another meaning of some country/ceremonial dance, seems to suggest this word had been existed before Waltz was imported.

I see this word used as 亦舒's book title, but having not read that book, I don't know if the usage is captured from real life experience or rather fictitious.

Since I've never heard this word used in my daily life, not even from the elders, I am wondering if this word is still used at all. If yes, in which Chinese-speaking region is it used and which meaning of the two does it refer to? If no, was this word ever a common word (when?) and which meaning was it used for?
My guess, and I think this is a reasonable good guess is that 华尔兹 = "waltz" and 圆舞 = "round dance" and in English a waltz is a type of round dance.

So you don't hear people calling "华尔兹" "圆舞" because "华尔兹" is a type of "圆舞" but 圆舞曲 can be used for any kind of "圆舞" not just for waltzes.

If you use Google to search for the definition of round dance you get the following:


  round dance
  
  Noun
  
  
  A folk dance in which the dancers form one large circle.
  A ballroom dance such as a waltz or polka in which couples move in circles around the 
  ballroom.
  


Also from the wikipedia article on Round dance:


  Modern social round dancing is choreographed and cued ballroom dancing
  that progresses in a circular pattern, counter-clockwise around the
  dance floor. The two major categories of ballroom rhythm found in
  round dancing are the smooth or international rhythms, such as foxtrot
  and waltz, and the Latin rhythms, such as cha-cha and rumba.