This is the 6606th most frequent Chinese word.
曲線
"曲線" means "curve" or "curved line."
Here 曲线 refers to a geometric concept, specifically a line that is not straight.
在数学中，曲线是一种不规则的图形。
In mathematics, a curve is an irregular figure.
This usage of 曲线 describes an elegant or visually pleasing curved movement, metaphorically applied to dance.
她的舞姿让人想起流畅的曲线。
Her dance moves remind one of smooth curves.
曲线 here denotes a graphical representation of data showing progression or trends.