Fish-tail \Fish"-tail`\, a. Like the of a fish; acting, or producing something, like the tail of a fish.

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.

Source: Webster's Revised Unabridged Dictionary (1913)