阿尔法粒子 ā'ěrfǎlìzǐ alpha particle 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)粒子 lìzǐ noun particle (physics) a subatomic or elementary particle, such as an electron or photon; the fundamental constituents of matter