隔音符號

Etymology
First used in the draft of the Scheme for the Chinese Phonetic Alphabet (漢語拼音方案) published in February 1956 by the Committee for the Reform of the Chinese Written Language (中國文字改革委員會).

Noun

 * 1) apostrophe used to divide syllables within a word to avoid ambiguity in various alphabetic systems used in China; in pinyin, to be used between two syllables (unless a hyphen is being used) whenever the second syllable begins with an a, o or e (regardless of whether any ambiguity exists) and not in any other circumstance