阿爾法射線 ā'ěrfǎshèxiàn alpha ray Origin Definitions Defs Strokes Stroke Words Sentences Sents 阿尔法 阿爾法 ā'ěrfǎ noun alpha The first letter of the Greek alphabet, Alpha (Α, α)射线 射線 shèxiàn noun ray (physics) A stream of high-energy particles or electromagnetic waves, such as X-rays or alpha rays.