phonetics a voiced speech sound whose articulation is characterized by the absence of friction-causing obstruction in the vocal tract, allowing the breath stream free passage. The timbre of a vowel is chiefly determined by the position of the tongue and the lips
2.
a letter or character representing a vowel
[C14: from Old French vouel, from Latin vocālis littera a vowel, from vocālis sonorous, from vox a voice]