速率 sùlǜ speed Definitions Defs Origin Strokes Stroke Words Sentences Sents 1 sentence 光在真空中的传播速率是恒定的。 guāng zài zhēnkōng zhōng de chuánbō sùlǜ shì héngdìng de. The speed of light in a vacuum is constant. Source: Dong Chinese Dictionary