• vocal sound that has no obstructions (linguistics)
• a vowel is a sound such as the ones represented by the letters `a' or `o', which you pronounce with your mouth open. most words are pronounced with a combination of consonants and vowels.
• letters pronounced without disrupting air flow from the lungs (a, e, i, o, u, y)
• punctuated vowel, vowel represented by punctuation rather than letters (grammar)
• phonetic phenomenon of changing pronunciation of vowels
• vowel with a long sound
• vowel whose sound cannot be sustained indefinitely (grammar)