瞳 tóng pupil of eye Origin Definitions Defs Strokes Stroke Words Sentences Sents 1 sentence 由于光线突然变暗，他的瞳孔不由自主地放大了。 yóuyú guāngxiàn tūrán biàn àn, tā de tóng kǒng bùyóuzìzhǔ dì fàngdà le. His pupils dilated involuntarily as the light suddenly dimmed. Source: Dong Chinese Dictionary