fishtail

• POS: Noun, Verb (intransitive)
• HYPHEN: fish=tail

CIDE DICTIONARY

fishtail, v. t. 

 to slow down by moving the tail sideways, of an airplane.  [WordNet 1.5]

fishtail, v. i. 

 to have the rear end skid from side to side, out of control: -- said of automobiles or other vehicles.  [PJC]

Fish-tail burner, a gas burner that gives a spreading flame shaped somewhat like the tail of a fish. -- Fish-tail propeller (Steamship), a propeller with a single blade that oscillates like the tail of a fish when swimming.

OXFORD DICTIONARY

fishtail, n. & v.
--n. a device etc. shaped like a fish's tail.
--v.intr. move the tail of a vehicle from side to side.

Idiom

fishtail burner a kind of burner producing a broadening jet of flame.