乙种 yǐzhǒng type B Origin Definitions Defs Strokes Stroke Words Sentences Sents 乙种射线 yǐzhǒngshèxiàn beta ray beta ray (electron stream from radioactive decay)乙种粒子 yǐzhǒnglìzǐ beta particle A beta particle, which is a high-speed electron or positron emitted by a radioactive nucleus during decay.