plural noun

: a family of extinct primitive ganoid fishes that lived from the Devonian to the Lias and have an elongate body covered usually with rhombic plates, small pectoral and ventral fins, a single dorsal and anal fin, a heterocercal tail, a skull covered with bony plates, and jaws bearing small teeth

Word History


New Latin, from Palaeoniscum, type genus + -idae

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.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Dictionary Entries Near Palaeoniscidae

Cite this Entry

“Palaeoniscidae.” Dictionary, Merriam-Webster, Accessed 16 Jun. 2024.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!