transactinide element

[ trans-ak-tuh-nahyd, tranz- ]

noun

, Chemistry, Physics.

1. any element having an atomic number higher than 103, the last of the actinide series. These superheavy, radioactive elements are extremely short-lived, and can only be created in the laboratory.

Word History and Origins

Origin of transactinide element¹

First recorded in 1965–70; trans- + actinide