What is "barber fish"

doctor \doc"tor\, n. [OF. doctur, L. doctor, teacher, fr. docere to teach. See Docile.]

1. A teacher; one skilled in a profession, or branch of knowledge; a learned man. [Obs.]

   One of the doctors of Italy, Nicholas Macciavel. -- Bacon.

2. An academical title, originally meaning a man so well versed in his department as to be qualified to teach it. Hence: One who has taken the highest degree conferred by a university or college, or has received a diploma of the highest degree; as, a doctor of divinity, of law, of medicine, of music, or of philosophy. Such diplomas may confer an honorary title only.

3. One duly licensed to practice medicine; a member of the medical profession; a physician.

   By medicine life may be prolonged, yet death Will seize the doctor too. -- Shak.

4. Any mechanical contrivance intended to remedy a difficulty or serve some purpose in an exigency; as, the doctor of a calico-printing machine, which is a knife to remove superfluous coloring matter; the doctor, or auxiliary engine, called also donkey engine.

5. (Zo["o]l.) The friar skate. [Prov. Eng.]

   Doctors' Commons. See under Commons.

   Doctor's stuff, physic, medicine.
   --G. Eliot.

   Doctor fish (Zo["o]l.), any fish of the genus Acanthurus; the surgeon fish; -- so called from a sharp lancetlike spine on each side of the tail. Also called barber fish. See Surgeon fish.