F1 Split Line
Splits the line where the cursor is located. The text from the cursor position to the right will be relocated to a newly inserted line.

From the Dictionary-IV User Guide, version 8.9.1. Open this page in the PDF
Splits the line where the cursor is located. The text from the cursor position to the right will be relocated to a newly inserted line.

From the Dictionary-IV User Guide, version 8.9.1. Open this page in the PDF