cardinal vowel

noun Phonetics.
  1. any one of eight primary, purportedly invariant, sustained vowel sounds that constitute a reference set for describing the vowel inventory of a language.
  2. any one of the eight or more supplementary or secondary cardinal vowels.

Origin of cardinal vowel

First recorded in 1920–25
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018