N-COUNT
元音
A vowel is a sound such as the ones represented in writing by the letters 'a', 'e' 'i', 'o' and 'u', which you pronounce with your mouth open, allowing the air to flow through it.
例句
The vowel in words like 'my' and 'thigh' is not very difficult.
单词my和thigh中的元音并不难发。
...English vowel sounds.
英语中的元音