trendlines

/T R EH1 N D L AY1 N Z/
noun
  1. 1

    A line on a graph, drawn through points that vary widely, that shows the general trend of a real-world function; often generated using linear regression

Source: https://en.wiktionary.org/wiki/trend%20line, https://en.wiktionary.org/wiki/trendline, https://en.wiktionary.org/wiki/trendlines