1. (n.)vowel a speech sound, as (ē), (&oobreve;), or (a), produced without occluding, diverting, or obstructing the flow of air from the lungs, and usu. constituting the sound of greatest sonority in a syllable
2. vowel a letter or other symbol representing a vowel sound, as, in English, a, e, i, o, u and sometimes y or w.
Etymology: (1275–1325; < OF vouel < L vocālisvocal)
2. (noun)vowel a vocal, or sometimes a whispered, sound modified by resonance in the oral passage, the peculiar resonance in each casegiving to each several vowel its distinctive character or quality as a sound of speech; -- distinguished from a consonant in that the latter, whether made with or without vocality, derives its character in every case from some kind of obstructive action by the mouthorgans. Also, a letter or character which represents such a sound. See Guide to Pronunciation, // 5, 146-149
Definitions of vowel 
Afrikaans: klinker
Arabic: صائِت، حَرْف عِلَّه
Bulgarian: гласна буква
Brazilian: vogal
Czech: samohláska
German: der Vokal
Danish: vokal
Greek: φωνήεν
Spanish: vocal
Estonian: vokaal
Farsi: حرف صدا دار
Finnish: vokaali
French: voyelle
Hebrew: אוֹת תְנוּעָה
Hindi: स्वर
Croatian: samoglasnik, vokal
Hungarian: magánhangzó
Indonesian: huruf hidup
Icelandic: sérhljóði
Italian: vocale
Japanese: 母音字
Korean: 모음
Lithuanian: balsė
Latvian: patskaņa burts
Malay: vokal
Dutch: klinker
Norwegian: vokal
Polish: samogłoska
Persian: حرف صدا دار
Pashto: غږيز، ږغيز، دعلت تورى غږ 
Portuguese: vogal
Romanian: vocală
Russian: гласная буква
Slovak: samohláska
Slovenian: samoglasnik
Serbian: samoglasnik
Swedish: vokal
Thai: เสียงสระ
Turkish: ünlü
Taiwanese: 母音字母
Ukrainian: голосна буква
Urdu: حرف علت
Vietnamese: nguyên âm
Chinese: 元音字母
