actinoid

1. 1.

   any of a series of radioactive elements with atomic numbers 89 through 103

   Synonymsactinideactinon

   Broadergroup

1. 1.

   having a radial form

   “starfish are actinoid--that is, they are radially symmetrical”

   Similaractinomorphic

Other forms of actinoid

plural

actinoids·

Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.

Questions about actinoid

What does actinoid mean?

actinoid means "any of a series of radioactive elements with atomic numbers 89 through 103". That is the primary sense; the word has 2 in total, listed in full on this page.

How many syllables are in actinoid?

actinoid has 3 syllables: ac-ti-noid. The stress falls on "ac".

What is another word for actinoid?

Close synonyms include actinide, actinon. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.

Is actinoid a common word?

actinoid is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.