The preferred place to ellipsize the string, if the label does not have enough room to display the entire string.
Note that setting this property to a value other than pango.types.EllipsizeMode.None has the side-effect that the label requests only enough space to display the ellipsis "...". In particular, this means that ellipsizing labels do not work well in notebook tabs, unless the gtk.notebook_page.NotebookPage.tab child property is set to true. Other ways to set a label's width are gtk.widget.Widget.setSizeRequest and gtk.label.Label.setWidthChars.
Set ellipsize property.