actinide
/ˈæktɪnaɪd/ noun
Forms actinides
- noun Any of the 15 radioactive elements of the periodic table from actinium to lawrencium that are positioned under the lanthanides, to which they have similar chemistry.
- noun Any of the 14 elements from actinium to nobelium (lawrencium is excluded by some authors as it is a d-block rather than an f-block element).
- noun (dated) Any of the 14 elements from thorium to lawrencium (actinium having been mistakenly excluded because it was thought to be a d-block element in the past).
Synonyms
Etymology
From actin- + -ide.
Sources: Wiktionary · WordNet 3.0 — from the Wiktionary entry “actinide”, CC BY-SA 4.0. Details