Definition of uranium lead in US English:

uranium lead

noun

  • 1The isotope lead-206; = "radium G".

  • 2Attributive (uranium-lead) designating a method of isotopic dating of rock based on measurement of the relative amounts of uranium-238 and -235 and of their ultimate decay products lead-206 and -207; (of dates, ages, etc.) obtained using this method.

Origin

Early 20th century.