Yes, you can remove the word "Linear" from the trendline legend entry by following these steps:

1. Click on the chart to select it.
2. Right-click on one of the trendlines and select "Format Trendline" from the drop-down menu.
3. In the "Format Trendline" pane that appears on the right-hand side of the screen, click on the "Options" tab.
4. In the "Trendline Name" section, delete the word "Linear" from the "Custom" text box.
5. Click "Close" to apply the changes.

Now, the trendline legend entry should only show the series names without the word "Linear".