'Threadfin' definitions:

Definition of 'threadfin'

From: WordNet
noun
Mullet-like tropical marine fishes having pectoral fins with long threadlike rays

Definition of 'Threadfin'

From: GCIDE
  • Threadfin \Thread"fin`\, n. (Zool.) Any one of several species of fishes belonging to Polynemus and allied genera. They have numerous long pectoral filaments. [1913 Webster]