A mixture of isotopes of lead, together with some bismuth and polonium, which constitutes the longer-lived product of the decay of radon; (also) lead-210 (radium D), the major radioactive component of this mixture, which decays by beta emission with a half-life of about 22 years.
Origin
Early 20th century.
Definition of radiolead in US English:
radiolead
noun
A mixture of isotopes of lead, together with some bismuth and polonium, which constitutes the longer-lived product of the decay of radon; (also) lead-210 (radium D), the major radioactive component of this mixture, which decays by beta emission with a half-life of about 22 years.