The Collaborative International Dictionary of English v.0.48:

Yerk \Yerk\, v. t. [imp. & p. p. Yerked; p. pr. & vb. n.
   Yerking.] [See Yerk.]
   [1913 Webster]
   1. To throw or thrust with a sudden, smart movement; to kick
      or strike suddenly; to jerk.
      [1913 Webster]

            Their wounded steeds . . .
            Yerk out their armed heels at their dead masters.
                                                  --Shak.
      [1913 Webster]

   2. To strike or lash with a whip. [Obs. or Scot.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Yerk \Yerk\, v. i.
   1. To throw out the heels; to kick; to jerk.
      [1913 Webster]

            They flirt, they yerk, they backward . . . fling.
                                                  --Drayton.
      [1913 Webster]

   2. To move a quick, jerking motion.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Yerk \Yerk\, n.
   A sudden or quick thrust or motion; a jerk.
   [1913 Webster]

The Free On-line Dictionary of Computing (30 December 2018):

Yerk

    (After Yerkes Observatory) An object-oriented
   language based on a Forth Kernel with some major
   modifications.  It was originally known as Neon, developed
   and sold as a product by Kriya Systems from 1985 to 1989.
   Several people at The University of Chicago have maintained
   Yerk since its demise as a product.  Because of possible
   trademark conflict they named it Yerk, which is not an acronym
   for anything, but rather stands for Yerkes Observatory, part
   of the Department of Astronomy and Astrophysics at U of C.

   Version 3.62.

   (ftp://oddjob.uchicago.edu/pub/Yerk/).

   E-mail: Bob Lowenstein .

   (1994-11-23)