The Collaborative International Dictionary of English v.0.48:

Crank \Crank\ (kr[a^][ng]k), n. [OE. cranke; akin to E. cringe,
   cringle, crinkle, and to crank, a., the root meaning,
   probably, "to turn, twist." See Cringe.]
   1. (Mach.) A bent portion of an axle, or shaft, or an arm
      keyed at right angles to the end of a shaft, by which
      motion is imparted to or received from it; also used to
      change circular into reciprocating motion, or
      reciprocating into circular motion. See Bell crank.
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   2. Any bend, turn, or winding, as of a passage.
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            So many turning cranks these have, so many crooks.
                                                  --Spenser.
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   3. A twist or turn in speech; a conceit consisting in a
      change of the form or meaning of a word.
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            Quips, and cranks, and wanton wiles.  --Milton.
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   4. A twist or turn of the mind; caprice; whim; crotchet;
      also, a fit of temper or passion. [Prov. Eng.]
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            Violent of temper; subject to sudden cranks.
                                                  --Carlyle.
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   5. A person full of crotchets; one given to fantastic or
      impracticable projects; one whose judgment is perverted in
      respect to a particular matter. [Colloq.]
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   6. A sick person; an invalid. [Obs.]
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            Thou art a counterfeit crank, a cheater. --Burton.
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   Crank axle (Mach.), a driving axle formed with a crank or
      cranks, as in some kinds of locomotives.

   Crank pin (Mach.), the cylindrical piece which forms the
      handle, or to which the connecting rod is attached, at the
      end of a crank, or between the arms of a double crank.

   Crank shaft, a shaft bent into a crank, or having a crank
      fastened to it, by which it drives or is driven.

   Crank wheel, a wheel acting as a crank, or having a wrist
      to which a connecting rod is attached.
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