Actinium-k

noun

noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    Synonym of francium. historical, obsolete, uncountable

Etymology

From the former practice of naming the steps in a decay chain sequential letters. Francium was first identified in the naturally occurring actinium series.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.