Electromagnetic radiation and Gamma radiation

Electromagnetic radiation noun - Radiation consisting of waves of energy associated with electric and magnetic fields resulting from the acceleration of an electric charge.

Gamma radiation and electromagnetic radiation are semantically related. In some cases you can replace phrase "Gamma radiation" with "Electromagnetic radiation", this phrases are similar.

Gamma radiation noun - Electromagnetic radiation emitted during radioactive decay and having an extremely short wavelength.

Electromagnetic radiation and gamma radiation are semantically related. You can use "Electromagnetic radiation" instead a noun phrase "Gamma radiation".