ne plus ultra

noun3

1. •
   The highest, ultimate point of achievement which can be reached; perfection.

   • November 30, 2014, Julia Kavanagh, Rome: The ‘ne plus ultra’ of Arthttps://camel76.wordpress.com/2014/11/20/rome-the-ne-plus-ultra-of-art/ It doesn’t get any better than this because Rome, like Florence, is the ne plus ultra of art.
2. •
   The perfect or most extreme example of its kind; the ultimate.
3. •
   (rare) A prohibition against proceeding further; an insuperable obstacle or limiting condition.