一丝 yīsī a hint of Origin Definitions Defs Strokes Stroke Words Sentences Sents 一 yī numeral one one; the number 1; single; alone丝 絲 sī numeraladjective trace a tiny bit; a very small amount, often used in set phrases like 一丝不苟 yīsībùgǒu or 丝毫 sīháo