noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   Any of the subclass Heterostraci of extinct jawless vertebrates that lived primarily in marine and estuary environments.
2. 2
   extinct jawless fish with the anterior part of the body covered with bony plates; of the Silurian and Devonian wordnet

Etymology

Heterostraci + -an

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