: a speech sound made with your mouth open and your tongue in the middle of your mouth not touching your teeth, lips, etc.
: a letter (such as a, e, i, o, u, and sometimes y in English) that represents a vowel
Full Definition of VOWEL
: one of a class of speech sounds in the articulation of which the oral part of the breath channel is not blocked and is not constricted enough to cause audible friction; broadly: the one most prominent sound in a syllable
: a letter or other symbol representing a vowel —usually used in English of a, e, i, o, u, and sometimes y