plural noun Ac·ti·nis·tia \ˌak-tə-ˈni-stē-ə\

Definition of Actinistia

  1. :  an order (superorder Crossopterygii) of chiefly Mesozoic fishes including the family Coelacanthidae having the interspinous bones supporting each dorsal and anal fin fused into one piece — compare latimeria

Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Join MWU now and get access to America’s largest dictionary, with:

  • 300,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Origin and Etymology of actinistia

New Latin, from actin- + -istia (from Greek histion web, cloth, sail); akin to Greek histos mast, weaver's beam, web — more at stamen

First Known Use: 1871

Seen and Heard

What made you want to look up Actinistia? Please tell us where you read or heard it (including the quote, if possible).


a trip made at another's expense

Get Word of the Day daily email!