noun Physics.
- a stream of alpha particles.
noun
- alpha particles emitted from a radioactive isotope
noun
- ionizing radiation consisting of a stream of alpha particles
n.
- A stream of alpha particles or a single high-speed alpha particle.
- A stream of alpha particles.
Particles sent out by some radioactive nuclei, each particle consisting of two protons and two neutrons bound together. Alpha particles carry a positive charge. (See beta radiation and gamma radiation.)