Definition of indeterminate vowel in English:

indeterminate vowel

noun

Phonetics
  • The vowel /ə/ heard in ‘a moment ago’; a schwa.

    • ‘Armenian has an indeterminate vowel, which sounds like the e in ‘laurel’; this appears as ë.’
    • ‘One change was a tendency to reduce any short vowel in an unstressed syllable to a common indeterminate vowel.’

Pronunciation:

indeterminate vowel

/ˌɪndɪˈtəːmɪnət ˈvaʊəl/