You can understand people using the word "tone", it comes up often enough in training books, and particularly in those aimed at women, even when there's a perfectly good version of the book aimed at men in which they use the terms "gain lean mass" in place of the female version's use of "tone"...some of the author's of books aimed at women cause a lot of confusion. I once read through such a book and had to refer to the male version just to find out what the heck the author was trying to say, with terms like "phase 1" and "phase 2"...I mean, geez, treat women as thick, then they go ahead and use the term "tone" and, well, you pretty much know the response that word tends to bring forth...
...then there's the phrase "you have good muscle tone", so...it's here to stay, like it or not
