a vowel sound in parts of words that are not stressed, for example the ‘a’ in about or the ‘e’ in moment; the phonetic symbol for this, /ə/ Topics Languageb2非重读央元音,弱央元音,混元音(如 about 中的 a 或 moment 中的 e 所发的音);音标符号 /ə/ Word Originlate 19th cent.: from German, from Hebrew šěwā'.