pectoral fin
The pair of fins located on the sides of a fish, behind the gills, used for steering and balance.
A fish's pectoral fins are used when changing direction.
This tropical fish has large, beautiful pectoral fins.
Standard kanji spelling using 胸 (chest) and 鰭 (fin).
Common mixed spelling with びれ in kana, easier to read.
Compound of 胸 (muna, 'chest') and 鰭 (hire, 'fin'), with rendaku voicing of hire to bire.