切音

切音	qiè yīn	to indicate the phonetic value of a word using other words
切	qiē	to cut; to slice; to carve / (math) tangential
切	qiè	definitely; absolutely (not) / (scoffing or dismissive interjection) Yeah, right.; Tut! / to grind / (bound form) close to / (bound form) eager / to correspond to / (used to indicate that the fanqie 反切 system should be applied to the previous two characters)
音	yīn	sound / noise / note (of musical scale) / tone / news / syllable / reading (phonetic value of a character)