资料来源 : Webster's Revised Unabridged Dictionary (1913)

Gamma rays \Gam"ma rays\ (Physics)
   Very penetrating rays not appreciably deflected by a magnetic
   or electric field, emitted by radioactive substances. The
   prevailing view is that they are non-periodic ether pulses
   differing from R["o]ntgen rays only in being more
   penetrating.