org-ellipsis

org-ellipsis is a variable defined in `org.el'.
Its value is

nil

Documentation:
The ellipsis to use in the Org-mode outline.
When nil, just use the standard three dots.
When a string, use that string instead.
When a face, use the standard 3 dots, but with the specified face.
The change affects only Org-mode (which will then use its own display table).
Changing this requires executing `M-x org-mode RET' in a buffer to become
effective.

You can customize this variable.