`ne plus ultra’

The expression comes from Latin, and it means, `not further beyond’. The ancient Greeks believed that this was the expression that was inscribed on the Strait of Gibraltar – then called, `Pillars of Hercules’. The inscription was meant to warn sailors not to go any further westwards. If they did, they would be sailing into unknown territory – the uncharted waters of the Atlantic.
Nowadays, `ne plus ultra’ is used to mean the highest level of excellence, something that is close to perfection. The “e” in “ne” is pronounced like the “ay” in “way”, “hay”, and “ray”, while the “u” in “ultra” sounds like the “u” in “cut”, “hut”, and “but”.

Here is an example. *Bala’s career with the organisation reached its ne plus ultra when he was appointed Managing Director.

Source: ‘Know Your English’ ( The Hindu) -April 16, 2007