Definition of non plus ultra in English:

non plus ultra

noun

  • The highest point or culmination (of).

Origin

Mid 17th century (in an earlier sense). From post-classical Latin non plus ultra ‘(let there) not (be) more (sailing) beyond’, alleged to have been inscribed on the Pillars of Hercules (Straits of Gibraltar) from classical Latin nōn not + plūs more + ultra. So used in French and Italian.

Pronunciation

non plus ultra

/ˌnɒn plʌs ˈʌltrə/