龈擦音 yíncāyīn alveolar fricative Definitions Defs Origin Strokes Stroke Words Sentences Sents 龈 齦 yín noun gums (bound form) gums; the flesh around the base of the teeth擦音 cāyīn fricative A consonant sound produced by forcing air through a narrow channel in the vocal tract; also called 摩擦音 mócāyīn.